Jeremy_H

Perfectionism is indeed a characteristic, not an accolade as most people think.

Once you're into your next model you can come back to this one to sort it out if needed. That's what I keep telling myself about mine anyway haha!

arcdude

Now be a kind lad and have a chat with my wife about the whole perfectionism thing
I do have the next model lined up it's a Crackerbox with a Zenoah G260PUM so that'll be my winter project, not enough time now to complete it for this year. The only chance for boating this year lies in the hands of Slew Shark whenever I can get it done, it's been some years since I've had a radio in hand. Getting close

arcdude

Okay onto the current dilemma, initially I wasn't planning on clear coating so I went ahead and used rubbing compound. Should the boat be scuffed up with a fine grit paper for the clear to adhere properly or would it be o.k. to spray as is?

Jeremy_H

If your clear coat is of a type that will not self etch, i.e. the solvent in it does not soften the paint being lacquered, then mechanical adhesion is a requirement. As such, yes, it will need to be abraded.

In order to minimise the chances of breaches, ensure complete surface abrasion, and make your life a damn sight easier, use ultra fine 'Scotch-Brite' available from your local automotive finishing supplier, some better DIY stores may keep this. There are copy equivalents, so keep an eye out for those, the 3M stuff is the best though imho:

http://solutions.3m.com/wps/portal/3...4245752&rt=rud

With no self etching, and no mechanical bond, the clear coat will shell off in time. You may also suffer from application problems as a shiny surfaces can effectively repel the paint being applied.

arcdude

Thanks Jeremy. I have seen the Scotch-Brite pads just can't remember where at the moment. Unfortunately my test with Krylon clear is a complete failure, I poured some 5% nitro on it and it melted almost immediately and has been drying for 3 days so that should have been adequate time to dry. It was the same method used for the Krylon enamel, same manufacture, same ingredients, at least what is listed on the can. Well that's a disappointment, back to the drawing board

Now is there another method of protecting the paint other than clear coating? Is there a type of wax that will build up, shine and help protect the finish?

Jeremy_H

Not that I'm aware of.

Maybe have a chat with a local auto refinishing place, they may be happy to give it a coat of 2K for a few bucks? Needs to be Isocyanate stuff though, not the VOC compliant type. Even that needs to be fully cured before it's totally resistant, I always quote three months. If you get fuel on it earlier it'll leave a very slight impression, but not react.

You can get 2K in an aerosol, a quick web search shows this example: http://www.spraymax.com/index.php?id=361&L=1 Being a 2 pack paint a catalysts has to be added, that integral to the can. Once activated the tin will give a certain 'pot life' so all the apps will have to be done in a planned sequence, but that's how it works with 2k lacquer anyway, the first coat should be light and always looks orange peely and generally crap, then after flash off full flow glossing coats go on, the first layer helps to bind it and help it to resist sagging with the heavier coat. Some aerosols have long pot lives though, enough time to let a first application dry enough to re-flat and coat again. Best to follow the specs for each product. If you have an infra red heater then use it, or get it out in the sun. It'll stay soft till it cools.

Standard warnings must apply, this is nasty paint and needs to be done outside with you upwind with a face mask if you don't have full air fed masks. If you can smell Pear fruit you're in trouble.

Nitro is not the single problem in fuel though, the Methanol is bad too, adding Nitro Methane worsens the effect in degrees.

Dry and curing are different things, have you done the test on a sample of the base colour? I've got a vague memory of an unusual property of one of the well known aerosols, not sure if it's Krylon or Plasticote though. Pretty sure one of them requires re-coating before 24 hours, or after a week, there's something about the interim 6 days that causes problems, I'll try and confirm some facts.

arcdude

That spraymax does seem nasty Taking it into a body shop hmmm, unfortunately I don't know anyone in the industry. I did testing on the Krylon base coat and it's fine, the test I did with the clear was over the sample grey I did a couple weeks ago, the clear turned to jelly almost immediately and the base was still intact with no ill effects. For the life of me I can't understand why the clear isn't and the enamel's are, basically the same chemical composition in both The only spray can that apparently is fuel proof is Lustrekote which doesn't seem to be available in Canada anymore due to being labeled dangerous goods, OMG and that they don't have a bilingual label in English and French, ARGHHH! The only issue I found with the Krylon is you have to mist a few shots before a full coat, everything I did was within 10-15 min otherwise you have to wait 4 hrs. I spoke to a buddy at the LHS and he doesn't have a clue what other's are using because the engine market in all arena's is going to gas, so the paint issue is somewhat lessened in that regard.

Jeremy_H

How old is the paint you did with test on?

arcdude

The base coat was initially tested about 2 weeks ago after sitting 3 days and again today when I tested the clear which was sprayed over the base coat and left for the last 3 days. On all previous models I've never used a clear coat and just may do that considering the only available clear coat spray can that was available is no longer in stores. It's too late now so I'll phone all the other Hobby shops in the area tomorrow.

Jeremy_H

OK, so how does the boat actually look from ten feet away right now?

arcdude

It outshines the cars in the yard hands down

Jeremy_H

Well then surely leave it as it is? At least for now. There's bigger fish to fry ;-)

arcdude

Agreed on the bigger fish to fry. The results are in on the availability of LustreKote clear paint which was the only off the shelf spray can in Canada that is fuel proof, now on the dangerous goods list and unavailable.

Further more scrutinized testing on the Krylon paints are in. The Clear disintegrates the second it sniffs fuel, gels right up, at least it's liquid enough it allows you time to wipe it up
The base coat enamel for the most part is fuel proof in that it doesn't really damage the paint per say. I took the hatch lid which was painted two weeks ago and placed a couple of circular drops onto it and let it stand for 3 min. On close inspection it seemed to leave a somewhat foggy look to the fuel spot, the spot wasn't sticky or really showing any ill effects until I tilted the hatch lid in certain light angles and noticed the spot. I tried to buff it with wax and it almost removed the foggy spot then I used a polishing compound for a quick swipe and the spot disappeared.

I personally can live with a foggy spot if it happens on the fore deck of the boat from the inverted engine when priming and what not. Caution can be exercised when fueling the tank and so on. For the lengths one has to go to for fuel proofing it's not worth it. If the foggy spot should it occur becomes bothersome at any time it is easily removed and if repeated removal of the spots thins the paint it's really not hard to tape it off an re-paint the area in the off season, seasonal maintenance The fog I mention is very hard to see unless it's seen from a side angle with the lighting just right, so really no big deal.

A few more touch ups and compound the rest of the boat and onto assembly

arcdude

Could use some suggestions on what to seal bolt holes into the hull to prevent moisture from seaping in?

Jeremy_H

Non hardening mastic. TDL is a common brand in the US, so may be available. But, any non hardening bedding mastic will do. Put a few turns of soft cotton thread around the bolt for surety, a modelling version of using caulking cotton (for research).

arcdude

Thank you kind sir, go figure I had plumbers putty which is a non hardening mastic sitting in my supply cupboard not 8' from me Assembly is underway which is the good part unfortunately I still haven't resolved the throttle linkage or fuel tank mounting. Will post pics when I get to that point. Cheers

arcdude

Becoming a little concerned with the weight, with everything piled on now that the paint is complete it weigh's in at just under 6 lbs. Overshot my initial goal weight of 4.5-5 lbs. Just the engine and mount weigh in at 3 lbs alone. Available options are to enlarge the existing front sponson's or design new ones or go down to a lighter motor such as a 46 TT and a lighter mount and shave close to 2 lbs off the overall weight if this doesn't work. Guess I'll find out before too long how this is going to work out

Jeremy_H

3lb lighter than my SI3 though

arcdude

Have been rather stuck on the throttle for the last couple of days, tried a bent 256 rod, too much in the way of angles and it flexed too much so I played around with a bellcrank and it ended up too complicated in that the hatch needs to be opened regularily and the first half of the bellcrank would pass through the hatch so I decided not to have anything protruding through the hatch and opted to go through the body. What I've done is install a flex cable through the upper body to the servo and a gentle curve up around the rear of the motor mount and through the underside of the top mount plate directly to the throttle arm. It appears that it will be a good solution although not as neat as what I'd hoped, probably being too fussy The tube for the antenna will also be brought up through the body rather than through the hatch. With the changes I won't have any difficulty with the hatch and making life a little simpler in the end, will post pics before long.

arcdude

Just about everything mounted in the radio box, been fun. Once the clevises are soldered I'll remove everything and put a coat of epoxy on the inside of the box and tidy things up a bit. The switch will be mounted in the hatch lid along side the battery and the receiver will be in the back corner where there is ample room to mount it. I had to change the small servo from a sideways position to what it is now in order to run the flex cable out the side and through the upper deck so a lot of wiggle room was lost in the process, pretty tight fit for everything. Note the difference in appearance between the hatch lid and the top of the boat which isn't buffed up yet.

Jeremy_H

A judgement on finish quality is best made in natural light, regular camera flash (or light I suppose as mine are mostly from a phone) rarely looks good in these close up pics. Check mine, I avoid flash like the plague.

Your install looks sound. Does you radio gear allow end point adjustment? Thing's become a lot easier with that. In principle there's no need to go in the box till a battery replacement comes up, but condensation can be a problem so I store mine with the radio boxes open, so lids off for that time. Are you going for a screw top lid for switch and charging?

arcdude

The only weight adjustment I'll be able to make is to swap positions with a 4 square battery pack and the receiver which will give me a weight shift of 2.5" at best, so not much. The clevise for the throttle is soldered at the bottom and I'll have adjustment capability at the top end and the rudder will have basic screw on clevises at both ends so lots of adjustment there. What I've decided to do is install a DU-BRO Kwik Switch in the hatch cover, as much as I like the idea of a screw top I know for ease of mind I'm the kind of person who'll open the hatch after a days running to check things over. In my airplane days a lot of possible catastrophes were averted because of daily checks on the gear. The hatch lid will be taped and by starting out with the Kwik switch I'll be able to change over to the screw lid should the gear location be proven.

arcdude

Is there alternate ways of preventing water from entering into the rudder control rod end other than a rubber boot? Can grease or something similar not be used? Wonder if a seal could be used on the inside of the radio box rather than on the outside

Jeremy_H

From my experiences with plastic control rods water is best kept out of them, friction soars when they get wet. On my twin test boat they locked up and I had to fit boots to the ends, so I'd not put them on the inside. Your Bowden cable will be alright with some grease, but I'd still use a boot, a few bucks for a lot of avoided pain. There seems to be two sizes out there, I find the larger cone shaped one handles the scope of movement better than the smaller parallel type.

Lip seals can be used, but they need a housing, a clean shaft to run on, and are best suited to rotary movement.

arcdude

I was afraid that's what the response would be I have purchased a boot however it is too large in diameter for the 3/8" hole in the rudder base. The boots that are available here are the cone shape ones with a base that has a flange you fit the boot over and place a rubber O ring to hold it on. Not sure how I'm going to attach it and there is little that will stick to aluminum effectively.