TT2

My Feedback: (13)

During the plug creation process, most of the time is spent sanding and filling. I've picked up a few tricks and favorite materials that can help speed this along considerably. I'd like to see this thread become a nice collection of sanding and filling tricks, so your contributions would be greatly appreciated!

SANDPAPER - Not all sandpaper is created the same! When I'm shaping cured epoxy / glass on plugs I like to use a very agressive paper. I typically use 80 grit and have recently begun using Norton 3X brand sandpaper. This stuff cuts like crazy and lasts a surprisingly long time. A 20 sheet pack will run you about $14. It's blue...I like blue. Good stuff! Norton also makes sanding discs (with and without holes) of the same type for orbital sanders. Typically I use sanding bars and good ol' rubber-block palm sanders. Works for me. Although I have many different kinds of power sanders, the rubber-block palm sander is what I use most often for plug creation. More control, less chance of going too deep. I have found some cool detail sanders at [link]http://www.rockler.com/ecom7/product_details.cfm?offerings_id=5556&filter=detail%20sander[/link] I have yet to try them. Also, I have been thinking about buying a variable speed random orbit sander for large jobs...are you using one? How do you like it?

FILLERS - Lots of recipes out there. For general filling / fairing of large areas I use the 'traditional' epoxy / cabosil / microballoons. Works well but very slow. Lately for smaller areas, creating inside radii and general fairing work, I've been using Squadron model putty (the white kind) for filling up to 1/8" thick. This stuff is super-smooth, sets up pretty fast and sands / feathers nicely. It can be easily shaped during application by your finger (latex glove) with a little denatured alcohol on it.

For blister / void repair I remove the overlying glass with an Xacto then fill the area with microballoons (dry). Apply a drop of thin CA, more microballoons if required, and then hit it with the accellerator. This is super fast and works great. The result is very hard...sands like epoxy / microballoons.

I also use good ol' Bondo for larger areas. Sands / feathers very nicely and is fast and cheap. For years I have tried to use Permatex spot putty / glaze compound. Every time I try it I wish I would have used something else...basically, I HATE the stuff but for some stupid reason I won't throw it out.

That's all I can think of for now...let's hear what you like to use.

-Tom

Mike James

I do a lot of the same things. Microballoons are among my favorites for plugs, because by varying the volume, you can control the hardness. I use epoxy products only, so Bondo doesn't work for me on plugs. Great for other things though, especially the fast stuff.

There is a local manufacturer who makes huge sanding belts with very aggressive grits, from 60 to 220, and he gives us the scraps he has when we ask. His idea of "scraps" are huge, in modeling terms, and the stuff lasts a long time.

I have to recommend all the Perma-Grit tools, too. We have the two (pouch-type "kits" ) "rough" and "smooth" versions of their tool sets, along with a few other odds and ends. They have become a necessary part of my building supplies now. They're great in general, but for what we're making at least, are also the perfect sizes. (Available through BVM and Aircraft Spruce)

Tungsten carbide tools for the Dremel are great too. Gotta love 'em, after going through a kabillion standard sanding drums.

I like the sticky-back sandpaper (i.e., Great Planes) too, because you can make your own custom-shaped sanding block, and apply that to it.

I save sanded glass/microballoons, and sanded balsa, in separate containers. Makes useful filler sometimes. For a small ding, I'll put a drop of medium CA in the area, sprinkle some of the filler in, and squeegee it flat with a scrap of balsa before it cures.

When it's time for the final finishing process, I love the standard 3M wet-dry paper.

ERichard

Another "filler" that works well at the initial plug stages is good' ol drywall compound. I've had great success with this stuff on blue foam and works best if you build it up with a couple of separate layers. As you can imagine, it is very soft and will sand very easy, so you want to get some glass and epoxy over it soon after you do your shaping.
This may work well for areas where you're using the Squadon type putty.
I generally get my basic shape with formers and a combination of blue foam and balsa. Then I apply pretty liberal amounts of drywall compound to areas that need filleting and overall shaping....as I said I generally do this in a few think layers, letting the compound dry completely between applications. The good think here is that you don't have to worry about "shaping" it in any way.......the stuff sands VERY easily as you would expect.
After I get the overall initial curves and shapes, I get some glass and epoxy on the plug. After that I go with Epoxy and microballoons for any further filling. Then a final layer of 0.75 - 1 oz cloth and epoxy and sand to a glossy smooth finish. Then I prime it and spray with PPG DCC red first and then PPG DCC black over the red...overall, two separate coats. This helps find the high and low spots when final sanding.....upon final sanding you'll see high and low spots in the plug by the changes in the red and black finish. When complete, I give a final PPG DCC black coat and sand to a mirror finish.....black will show surface impressions far better than white or gray. But, this is a bit off the subject....
Again, drywall compound during the inital rough build up stages has worked for me (I'll try to post some pix from a current F3A fuse plug I'm working on).
I buy the ready mixed buckets at Home Depot or Lowes.....pretty inexpensive and fool proof to use.

-Erik

TT2

My Feedback: (13)

Mike: I use Bondo in conjunction with epoxy / glass. Stinks, but it's fast and I haven't experienced any problems with the Bondo debonding from the glass. The Permagrit tools are superb but I just don't do enough small, detailed plug-making to justify the cost...but man, they are awfully tempting! I'm with you on the carbide Dremel sanders...the first one I bought (over ten years ago) has been used on just about every material that's been in my shop, and ABUSED by overheating, etc...it still cuts better than a NEW paper-backed drum. I make my own sticky-back sandpaper by hitting the back of the sandpaper with 3M77 and stick it to whatever...it removes easily with a heat gun. EPP foam scraps make great final-stage sanding blocks...they have some 'spring' to them.

Erik: Drywall compound...great idea. I have used lightweight spackle to fill foam that got 'chunked' or over-sanded and found it to be way too soft, so I went back to epoxy / microballoons...which is much too hard for use on foam. I'll give the drywall compound a try. What do you use for making formers? I used to use 1/8" lite ply (lumberyards sell 5' x 5' sheets of the stuff for $25 or so) but recently switched to 0.010" aluminum flashing. You can print out your patterns, 3M77 the paper to the aluminum flashing and then cut the flashing with a pair of scissors. Very, very fast. I laminate the flashing / foam (slightly oversize) / flashing etc. layers together with more 3M77 then begin sanding away at the foam. The aluminum also provides a tell-tale 'chit-chit' sound once it's hit with the sandpaper so you know you've sanded enough in that area. I have used formers and pourable foam in the past but the flashing / extruded foam provides a much more consistent block for sanding...and sanding...and sanding.

The only problem I've run into when using aluminum with foam are their vastly different coefficients of thermal expansion. You need to leave everything at room temperature or you'll run into problems…forget about using your curing oven when curing the glass on the plug or creating molds. I didn't seem to have that problem when using 1/8" lite ply.

I only use the Squadron putty on very small areas when I need something that is very easy to spread smoothly and the area doesn't require a very thick buildup. Otherwise I use Bondo. The Squadron putty and Bondo both eat foam and can only be used after the initial epoxy / glass layers.

Keep those ideas coming!

Oh, for the 'new guys', you can get massive quantities of chopped glass, microballoons and cabosil at your local boat repair shop. Take some coffee cans and you should be able to get enough filler to last a very long time for about $10.

-Tom

saramos

Any insight or tips about the differences between glass (white) and phenolic (red) microballoons? Do you have a general preference or do you find they have different applications?

Scott

TT2

My Feedback: (13)

The phenolic microballoons sand easier and are lighter than the glass microballoons. The drawback is that they're more expensive. I use the phenolic microballoons when I'm filling wood and need to build up an area that is too deep / large for lightweight spackle. I use glass microballoons for filling fiberglass parts and as a lightweight, yet VERY stiff, mold thickener (mentioned in the sand mold thread).

saramos

Thanks for the info. I almost bought some phenolic microballons until I saw the price. I may still pick some up.

Scott

ERichard

Tom,
I also use the lightweight spackle (Red Devil brand), but I use it as a balsa filler for flight models.....it's too good to use for plugs. Also, it can be a bit expensive to use a bunch of it on plugs. The Sheetrock Joint compound works great on blue foam for the plugs.....don't use it on any flight model, it's far too heavy.
Like I say, don't put it on too thick, if you do then it can (and will!) form cracks when it dries. I mainly use it to fill joints between the glues pieces of the plug. In some cases you can add a couple of layers to build up to 1/4" thickness. Wait for the first layer to dry completely before applying the second layer. For example, let's say that you are mating a vertical fin to a fuse plug and you want to have a nice fillet that feathers it all together like one contiuous, smooth shape.. the joint compound works great for this, put a bunch on then let dry and sand, you can keep repeating this process until you're happy. It sand MUCH easier than the spackle....but have a vacuum ready, the dust can get everywhere in a hurry. It will be very soft and scratched and dings easily so, as I said, it is best to get the filling done put some glas and epoxy over the plug soon. Once I have glass and epoxy over my plug I don't use the joint compound anymore.....strictly microballoons and epoxy from there on out. Sometimes I will use Bondo, but only in extreme cases....like Mike James says, it is not wise to mix polyester and epoxy, although to date I have not had trouble with Bondo specifically. However, I learned at an early stage (some 25 years ago) DON'T put polyester RESIN over epoxy......for some reason Bondo seems to do okay in limited quantities. To be safe I alway put a final finishing layer of light glass and epoxy over the final plug and sand that to a smooth finish before priming, painting and waxing/buffing and waxing/buffing and waxing/buffing.....

The aluminum sounds like something I should try....I can't tell you how many times I have inadvertently sanded a flat spot in my light-ply formers (I do use light-ply also). I think that since you are only making the mold from the plug then you could do it just as you say (without any additional heat from an oven). I would hope that this doesn't cause problems when making final parts in these molds in a curing oven (I use MGS which requires a specific post curing temperature).

I must admit that I have never been a fan of the pourable/expanding foam method, I have never had great success with it. For me it is easier to shape blue foam or in some case just frame it up with balsa sheeting and soft balsa blocks. It seems to work well for others, oh well.

Here are a few pictures of a new F3A design I'm working on.....the plug is in the early stages and shows a few of the areas that I use some fillers. Basically, the fuse starts with a built up balsa fuse (truss built box with sheeted sides) this allows me to keep angles and thrust line square and also keeps everything dead straight since it is framed in a jig. Then I hot wire cut blue foam for the curves (e.g. turtle deck, cheek and chin cowls, pipe tunnel, etc. The white you see is Joint compound filling the seems in the blue foam and balsa. The last picure show the first layer of 6 oz. glass going on (to keep me from denting things by over handling it....or knocking over[:@])

I'll try to keep some pictures coming to show my progress. I've done six other F3A plugs ( as well as some WWII scale plugs) using similar construction techniques and all have turned out great.

-Erik

GSNut

My Feedback: (8)

How I find those troublesome pinholes that always seem to pop out on glass fuselage, wheel pants/spats and cowls...(Yes, I know no manufacturer wants to admit there are some...ducking for cover..). I will presume that you have washed the item with dishwashing soap and water or whatever.. now do it again, Lightly dampen a soft paper towel or a rag with M.E.K. or the like, maybe acetone (the last two do outdoors in the fresh air.)

Now draw a few lines on your nicely cleaned and lightly sanded item...with a Bic Markit or Sharpe pen...when dry, with a soft paper towel dampened with acetone or my favorite is M.E.K. wipe the marks out in a circular pattern untill the black is in the towel/rag.. You will see all the little surface pin holes and divits in the glass works. Like they have been hi-lighted.

The more you sand the more pinholes, so look often and repair before the primer coat.

I use Sig Epoxolite applied near or on the offenders and then with a wet finger just massage it around and into the little buggers. Let Cure and sand...smooth

Remember...if you don't completely clean the glass item and you start to sand it. You just may press all those oils, waxes and silicones right into the very matrix of the glass work. Yuck, now you got fisheye and other unsightly uglies in your primer and paint work.

Clean, Clean is the word. Hope this helps someone outthere.

B Vial

I fill pin holes with the following procedure:

Sand the seams if any down. Get it ready for the primer coat.
Take a 2 inch or so brush and dip it into a jar with some high build primer in it.
Next dip the wet brush into some micro balloons in another jar loading it up as much as possible.
Now brush this onto the airplane.
Repeat until you have the whole fuselage/wing done.
Let it dry overnight.

Looks ugly at this point, REAL UGLY. A real thick layer of primer and micro balloons, lots of huge bumps, large brush streaks, etc.
Now comes the fun part... Sand this down with some 400 grit paper.
It will sand off REAL EASILY due to the micro balloons.
Sand it down until you get back to the fiberglass.
We are just wanting to fill any pin holes, not prime the plane at this time so take it all off with the sand paper.
There should now only be little dots of the primer/micro balloons left that filled in the pinholes.

Prime the plane as you would normally. If any pinholes remain don't worry, just let it be until the primer is dry.
When the primer has set, just hit the very few if any pin holes with some spotting glaze.
Let the sanding glaze dry and sand it back down to the primer. Sand the plane and continue like you normally would.

Doing it this way fills them easily, makes the sanding almost a joy to do and the weight gain is unmeasurable.

boater

My Feedback: (2)

Pin holes, many are now waxing thier fuselages with spackling compound before the first primer coat, (kinda like Violett's pinhole filler) smear it on trying to get it into all the those little holes, let it dry for an hour and buff the haze off. I like Synkloid's exterior spackle (turpentine based) for this, but you aircraft guys probably are fine with interior spackle. I never seem to be able to get all the pinholes, but this does seem to get a bunch. After the first coat of primer, I mix talc with some left over primer till thick and dab a smidge on with a toothpick to fill the little buggers that now show up. The talc makes the dots of primer easier to knock off so hopefully you aren't sanding through your primer and exposing more pinholes. I still seem to need three coats of primer to get everything ready for color. Sometimes it seems like I'm never gonna get done. Rudy

Hustler58

My Feedback: (1)

Here's my two cents worth. I do several plugs and molds a year and the best stuff I have found is Rust Defender made By Z-Chrome.You get it a auto body shop. It is used to repair rust spots on cars. It is a polyester filler,you mix just like the resin. The great thing is it will fill every pin hole and you spray it out of
a paint gun. It will build up like bondo. It is ready to sand in 1 hour,and it will not clog up you sand paper no mater what grit you use. Once you try it you will love it. For someone that is a professional sander it is a great product.

Butch

Bruce Thompson

I feel like adding my two cents worth also. After trying many products / methods I have found a product I use almost exclusively, Its called EZ Sand by Duratech. You can buy it from Applied Vehicle Technology 317 546-6840. It IS polyester based so can be used directly on polyurethane foams only. I use it on "covered" blue foam though. I have never had a problem putting in it on epoxy. With that said I would like to make a few comments. Many epoxies when air cured will blush. I have yet to get a manufacturer to comment on this with any real answers. This is an oily surface contamination and I have yet to find anything that will remove it other than sanding it off. The only way I have been able to avoid this is to peel ply the entire plug. The epoxy will still blush but it is on the outside and is removed with peel ply. The peel ply then leaves a surface ready to prime. For voids or low spots I mix Cabo-sil, Micro, or Sib-a-sil in the Duratech and it makes a filler that sands at the same rate as the rest if the primer. The Duratech is also a very high build primer. For pin holes put on a glove and rub the Duratech onto the surface and into the pin holes. You will never fill small pin holes by spraying. The spraying action pressurizes the pin hole and will not allow the material in. When you have the plug properly finished, thin the Duratech with med laquer thinner and spray like a paint coat. Then polish to a sheen. I kno everone has an opinion but this works very well for me.

TT2

My Feedback: (13)

Erik: The only time I use polyester resin is when I'm repairing something that was made with it...otherwise I leave it alone. I've used quite a bit of Bondo in the plugs I've done over the past few weeks. There were a couple of 'afterthoughts' added to the underside of a cowling that were added using Bondo. This was done after the plug had already been glassed and primed with Duratec. No problem...matter of fact I didn't even bother glassing over the bondo...I just built up the Duratec pretty thick in those areas when I re-primed. Probably not the ultimate solution, but it worked.

You guys filling pin holes in existing parts are on the right track. I use thinned primer with some microballoons, wipe it on top to bottom then right to left with a paper towel. Usually gets them all.

When I'm making plugs the best way to minimize the pinholes is to use a really tightly woven glass for the last surface layer. 3 or 4 oz. crowsfoot satin cloth works great here...much, much better than plain weave 4 oz cloth. I also use it as a pseudo print blocker as my first layer of glass for a mold after the epoxy surface coat. This is cheap insurance if you have areas of the surface coat that were a little thin.

Bruce: It sounds like you have your plugs very close to being the final shape before you even glass. Mine are usually off enough that I need to sand the entire plug anyway so any blushing doesn't affect me. How far do you go with the sanding / polishing before you PVA? I had sworn off PVA but since I bought a mini HVLP gun with a super-fine 0.8mm tip I may be rethinking that. It fogs the PVA so well that I might start using it again. It is a cheap and dirty way to get a glossy mold without the need for secondary finishing operations...HOWEVER it tends to trap small particles under / in it that translate to pits in the molds. The pits are barely noticeable but if you want a true mirror finish then you'll have to sand / polish the molds. I have found that PVA loves heat (within reason). If you heat up the surface, the spray gun, and the PVA to 90-100 degrees before shooting it levels out very nicely.

If I know I'm going to be sanding / polishing the molds anyway I prefer to use Safelease 20L (wax based) or Safelease 30 (PTFE based) on the plugs. The 30 seems to release a little better and will take more heat. Application takes some getting used to. I use a clean T-shirt and cut it up into squares. During application the agent may start drying on the applicator rag. Toss it and wet out a new one then continue. Work from one side to the other and overlap the previous stripe slightly. Make sure that you cover everything the FIRST TIME...if you have to go back over it the finish will begin to degrade significantly. The finish on the molds will be good enough for anything that will be painted after molding.

What about POLISHING MOLDS? After the molds have cured in the oven for a few days I am starting at 400 grit and going down to 2000 grit...but only if there are significant impressions of the Safelease release agent. If the molds look pretty good already I just begin polishing. I've got a variety of polishing compounds but the only ones I have that seem to work when applied by hand are some white Turtle Wax polishing compound, Novus #2 plastic polish, and Flitz metal polish. The Flitz seems to work pretty well and a little goes a long way. I'm open to other suggestions!

BTW, the molds I'm currently working on will be used in the production of carbon fiber parts and I want the finish to be like a mirror. I don't want to use PVA so I need to get the mold's finish near perfect. I will be using wax only on the molds for production parts after using PVA for the first few pulls out of the new molds.

-Tom

ERichard

Tom,
You are EXACTLY right here! This is what I do also....Safelease 30 has never let me down!

As far as just using wax, I use Dolphin Wax (from H&M Racing)....this is like the Safelease 30 of waxes. It really works well for paint-in-the-mold layups. If you are not familiar with it, do a quick search on this forum for "Dolphin wax"...it was a hot topic several months ago.

-Erik

TT2

My Feedback: (13)

I'll bet the Dolphin wax would be great for unfinished carbon parts also (canopies, etc.)...I've been reading about it quite a bit lately. PartAll is a P.I.T.A.

What's your mold polishing system? I'm looking for alternatives...my current system is OK...I want PERFECT! I'm after that 'wet black paint' look.

-Tom

Bruce Thompson

TT2, I rarely glass my molds anymore. I use 6 lb. urethane foam and Duratech that right out to the finished shape. The Duratech acts like a skin and works fine. On another note: I used PVA several years ago and grew to not like it. After researching a little bit and talking to a friend of mine that makes carbon parts for control line A/C, I found I was using the wrong wax. I switched to PTMW wax, ( I don't know the no. off hand) and what a difference! I know use PVA a lot. It has some wonderful benefits beyond the "barrier" ones. I now typically wet sand out to "only about 800 to 1000 grit and PVA. This gives me a very nice gloss on the mold. I use PVA on many parts also.I know I will probably stir up a hornets nest with this, but,,, PVA is the only way I have found to eliminate pin holes. If you polish your molds to a high sheen and bag your parts you will have pin holes. the higher the sheen the more pin holes,(this is not relying on a "B - staged" gel coat. Try this experiment. Go to Menards or Loews and buy a ten dollar sheet o 1/8th inch melamine. This is masonite with a white "something" layer bonded on it. Cut off a one sq.ft. section and wax it one time with a non silicone non carnuba wax. Spray on three coats of PVA drying with a heat gun each layer. This will only take ten minutes for all three coats. Keep the heat gun moving constantly though because too much heat will wrinkle up the PVA and you will have to start over. Brush on a "full"coat of epoxy. lay your fist layer of dry fabric and squegee, (sp?) or bry out with a dry brush. This allows the resin to soak up through the fabric. Then finish wetting out with more resin. Wet out additional layersith more resin. This process is faster and easier if you just use a squgee on each layer. Vacuum bag with full vacuum. You will get a surface that looks like it has been autoclaved and is void of pin holes!

Bruce Thompson

Sorry! On the last post I meant to say I rarely glass my PLUGS anymore.

ptxman

My Feedback: (2)

Perfect, eh? When I did my Vector molds I used a polishing compound called Farecla. It is a water based polishing compound. Im a Canuck so I dont know if its available in the States but Im sure there are equivalents. It was kind of a lucky coincidence, when I was in the autobody/paint supply store the rep happened to have a demo going on which really sold me. And no, I dont usually by Jintzu knives that cut through beer cans & then thinly slice tomatoes!

They had a steel panel coupon pre-painted with standard auto (atalysed urethane paint, but a really sour looking orange peely application. They must have intenionally cranked the gun pressure or something on purpose just to prove the point. Anyway way worse than any modeler would spray! They first blocked it down with 600 wet paper for all of 1/2 minute, then the same with 1000 paper, then wiped it dry. At that point you could see most of the hilltops knocked off but still not a perfect prep job by normal standards. Then they put a small dab of polishing compound on the foam wheel mounted to an electric car polisher & spritzed the surface with water. After a very short time of polishing, maybe only 3 passes over the same area, this thing looked like a mirror. I couldnt beleive it.

As I recall, the "sales pitch" of water based compounds over the typical solvent based goes:

- a lasting shine, because part of the gloss you see on solvent based is the carrier itself. After it evaporates, the surface loses some of its luster. I understand this can happen pretty quick. Apparently thats why some of the show car detailer types like this.

- the way the water system works is it progressively breaks down the (micro) grit of the compound itself due to the water spritz & polisher. This makes a smaller grit particle (= finer equivalent grit#) and perpetually exposes new cutting surfaces

- no solvents means less risk of contamination & compatibility with the subsequent releasing agent. In real life a release 'wax' is a petroleum based product but some of the newer agents are water based. It may not be a big issue , but still Id rather start with a clean 'contaminant free' surface as possible. In the auto world, polishing is the end of the trail.In the model molding world, we still have one more step, the releasing agent application prior to gel coat.

- similar pricing, easy cleanup, various grits available etc same the other stuff

If there any experienced auto type guys out there to comment if I have my story straight, please step up.

BTW Ive found that the powerized polisher is definately a key part to acheiving the super-duper shine results. Unfortunately those typical plosihing units are a bit unwieldly for rc molds. It can be done by hand but it takes lost longer. This system recommends their foam sponge type polishing head which hold the compound & the polish itself in the pores. I tried similar looking stuff by hand with pretty close results but I think next time I would consider cutting up the polishing sponges & making smaller scale versions.

BTW It is for this reason (& a few others) I prefer a solid plug made from the hardest, densest material you can work with. If you ever get into polishing there is minimal amount of pressure required to apply to the surface. I dont think the bue foam core with a bit of glass would take much of this without distorting. But thats another subject...

ptxman

My Feedback: (2)

I'm just getting into an hvlp system now. Can you comment on what sort of gun you bought & why? Ive ordered a touchup model which Im hoping will be perfect for RC painting use & have low bounce & overspray etc. The sizing will supposedly be in the 1" - 4" range, a nice handoff transition from a typical airbrush. You do need a decent compressor to get the required CFM's they require though.

Also the more I read about HVLP systems & see the viscosity range they can deal with, the more I think a guy could be spraying in the epoxy gel coat surface onto the plug prior to molding layup & be done with paintbrushing it on like, well... Neanderthal Moldmakers.

seanreit

My Feedback: (60)

PTX, I use HVLP guns I get at Lowes. I have used Saito Minijet and cheap HVLP guns, and I just don't see an incredible difference. I use the cheapies (but always gravity fed cups) for Primer. I use a very small gun for detail work (.7 mm tip) and same for clear coat.

They run about 75 bucks a gun at Lowes, maybe cheaper on ebay and the sorts.

TT2

My Feedback: (13)

I found a couple of Astro Pneumatics Mini HVLP guns (0.8mm tip, 1.0mm tip) on eBay and got them BOTH for $43. What a steal. They are copies of the Sata Minijet which is supposed to be the best available gun in this size. I read some very positive things about the A.P. mini guns so I bought them...and I'm glad I did! I have been using the 0.8mm with the flow turned in quite a ways and 40psi regulated at the gun to spray PVA. Does an excellent job with VERY fine atomization...one mist coat, let dry, one flow coat, done. I use the 1.0mm tip for shooting Duratec primer. The needle is worn so the gun pulses a little, but for primer it's OK. I haven't tried shooting any paint with either gun yet. I would imagine that the 0.8mm will only get used for clears...it doesn't flow enough for a very wet coat.

The specs of the guns I have say they can be run with a 1hp compressor but that seems awfully small. I have a Craftsman 5.5hp / 25 gallon upright tank compressor and it cycles pretty often when I'm spraying. I regulate the line pressure down to 60psi at the compressor and use another regulator and water trap / filter on the gun itself. Works great.

I haven't tried a Sata Minijet so I don't know how the A.P. mini guns compare, but they work well for me. I am a total newbie when it comes to HVLP but I certainly like using them. The lack of overspray is amazing.

I'm trying to get away from having to wetsand / polish molds at all. I shouldn't have to right? I simply want to duplicate the already glowing finish on my plug. If I use PVA over Partall wax then I have to sand / polish the molds afterwards...same holds true if I use Safelease. If I just use Partall wax by itself I may 'stick' the mold. What about Dolphin wax? Can you rely on JUST the Dolphin wax to pull molds from a fresh plug? After speaking with Harold at H&M Racing, the stuff sounds promising (he mentioned a Peter from Calgary...I'm assuming that's you ptxman.) I don't do alot of painting in the molds but I do make loads of carbon fiber parts. I need a non-silicone (since areas of the parts will be painted later) release system that yields an killer shine and releases well. I think the Dolphin wax is the ticket...I've got some on the way. If it works as well as people claim then I may be getting HUGE quantities of it.

-Tom

daven

My Feedback: (1)

The Dolphin wax is easy to work with, but I'm still using PVA on my molds. I pulled 4 wings before I went with Wax Only and I had a few areas stick and I had to repair the mold. The PVA gives me a good enough surface to work with and I am painting in the mold.

Dolphin wax is much easier to use than Part All.

ptxman

My Feedback: (2)

Thanks for the info. I ended up ordering an hvlp touchup gun locally for a pretty good price, cant wait to try it out


That sounds similar to what Im looking at Sears 6hp, 30 gal upright.


Yes thats what Im saying. Put all the effort into finishing the plug & the mold will reflect that effort. And for that reason I prefer auto finishes on the plug, its a great shine when sprayed, but its an oustanding shine when polished. Here I found a link for Farecla in the USA.
http://www.fareclausa.com/home.htm
Dependng on parts volume, you may have to condition the mold once in a while. Small scratches can be buffed out & builup of wax etc an be removed. I would consider this as more of a polishing operation.


I used a different release agent between the plug & mold initially so I cant comment on the pva & Dolphin combo. I did use it on layups & tried pre-paintng & for that its great. The pva would give you a bit of extra insurance but it wont be quite the supershine finish unless its applied very well. I hate to comment on something I havent tried personally but others here are doing it apparently. Just recognize Dolphin is not really intended for pva as other systems are. As usual, try it out on something small & expendale first. Yes Im Peter Thannhauser from Calgary.

Sounds cool. What kind of CF parts? If you are painting the CF parts post layup when removed from the mold, thats kind of a different deal. What makes the Dolphin so unique is it allows pre-painting directly on the wax surface without beading (as in the case of pre-painting the waxed mold & then continuing on with the layup). This non-beeding charactersistic is the real hard quality to find in any other releasing system. But after pulling the layup part there will always be a trace amount of release agent residue on the surface & Dolphin is no different. So you must remove this with mild degreaser etc prior to painting that area on the part. Give us your results when you get some in!

TT2

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They're handy, not very expensive, but they are pretty noisy.

I have been operating under the assumption that if I'm going to have to use PVA or some other release agent that leaves some imperfections, I will have to sand / polish the molds anyway. I was hoping that the Dolphin wax would provide a sufficient release to eliminate the necessity for additional release agents during mold construction. If that works then I'll start using PPG primer / paint for plugs instead of Duratec...and have that 'ba-bing' shine on the molds with no additional effort!

Which wax, which release agent?

Laying the PVA on is definitely an art in itself. I have found that the process outlined by Rexco works very well and solved the problems that I've had with PVA in the past. That's fine and dandy, but I don't want to have to rely on it at all. It's just another step during mold-making that I could do without. I wouldn't even think of using it during production...it just takes too long to mess with.

I've been making tons of landing gear, some canopies, cowlings and wheelpants...I've done other modeling things in the past. I do some full-size race car parts also...I should do more! The molds for my latest effort (30% Edge 540) has a very intricate cowling that I won't be able to use carbon on, and there are radii in the wheelpants that are too tight to layup without using thickened epoxy (i.e. dead weight) and letting it gel before laying in the cloth. I suppose I could vacuum bag the parts but that's too much effort for a non-structural part and just isn't cost-effective. I've tried all kinds of 3K cloths...plain, twill, satin (maybe I could find some 1K satin???) and nothing is pliable enough though the 8H satin comes very close...unfortunately it's too heavy due to the higher pic count. The carbon canopies will be no problem...good ol' 3K 2x2 Twill (I've got loads left over from a race car project) lays in nice enough. A highly-polished mold using only Dolphin Wax is what I plan on using for production. I don't trust Partall enough to use by itself without PVA, Safelease isn't shiny enough, can't use silicone. I'm still waiting for the Dolphin Wax to show up.

The plan is to make the cowling and wheelpants from glass. I have some 8.9 oz 8H satin that is just marvelous stuff to work with...cut it on a bias and you can stretch it around the end of your thumb!. This glass coupled with a very low viscosity resin results in a part that's pretty flippin' light and strong without bagging. I would like to pre-prime these parts in the mold using Dolphin Wax and a urethane primer...preferably white, preferably inexpensive. Any suggestions?

I've successfully painted Safelease 20L and Safelease 30 without beading...the 20L works slightly better. Released great but it's impossible to get a gleaming shine with Safelease so it's reserved for parts that are fully painted after molding.

I'll follow up with some finished part pics after the Dolphin wax gets here.

-Tom