Hey Tony

Great presentation and info in vacuum bagging !!

I have been using Gorilla Glue but will pick up some Tite Bond and try that.

What size Giles 300?

In the last picture is that the balsa soaked in ammonia sitting on top of the turtle deck?

When you determine the length of the wing tube for it's stops, do you add an 1/8" to 1/4" for some play?

Thanks so much for this info and your time Tony, as it will save me a lot of the trial and error you were faced with.

The wing span is 87", built from Promark plans (Formerly Ohio R/C). For wing tube length, once everything is built and fit, I sand the wing tube to length to achieve a tight fit. Usually loose an inch or so. The problem is you just don't enough socket to match the tube, the tube and the socket are the same length. My 36" wing tubes end up 34" or less. I hope this answers your question.
In the last photo the skin is soaked with ammonia and placed back into shuck with the core, not forced, just enough to prebent the wood on the rear section where the bend is rather sharp. I usually allow this to dry for several hours before bagging.
Tite Bond II works well for gluing the skins together, it's water resistant. Elmers and regular Tite Bond are not, skins glued with non water resistant glue don't make it through the bending process as the glue joints fail.
I have sheeted wings without edge gluing the sheets together, just tape. The glue foams up under the marking tape onto the finished side, some joints were uneven. It worked OK, I just found that edge gluing works better for me.
Tony Hallo

Hey Tony give up some more info on the Promark plans. Cowl, canopy, who cut the cores?

Kent

There is a good book on vacuum bagging. Its "RADIO CONTROL FOAM MODELING" by David Thomas.
It describes how to make a vacuum pump out of a discarded refrigerator pump.
It also describes how to make the press DH refers to.
The book is published in England but I found it in a US hobby shop so it must be available thru our destributors.
If you can't find it PM me and I will send the publishers address

Aerospace Composite Products (ACP) (510-352-2022) has a great how to video and all the supplies you need for vacuum bagging. The pump already has the resevoir, vacuum switch and tubing plumbed for you. They bags are available in any size you need and George Sparr can answer any questions you may have. They are good people and support the hobby. They will also be at Toledo. George gives demos all day long there.

I just got done bagging the foam parts for my plane. A couple of us got together and bought the ACP system. Works very well. I had a lot of questions myself but my friend did two planes with the pump before me and helped me out. A suggestion that Al gave me that I'll pass on is that you first do a "dry run". Vacuum down everything without glue to make sure there are no surprises.

When you're ready make sure you have everything ready to go. Enough glue, wax paper, a place to set the buttered up sheet while your working on the other one. Also mark a line on the sheeting and core with a bright colored marker so you can see that the sheets didn't shift while looking through the bag. When doing a Carden as Dick mentioned, one of the shucks is marked "down". This is the trued piece so this piece goes under the bag to keep the wing straight. Just for clarification, you make a sandwich with the upper and lower sheets as the bread and the foam being the meat (Analogy borrowed from Rob T. ). This sandwich goes in the bag as it is. Then you vacuum it down. Once it pulls full vacuum, place the trued shuck underneath the bag and put weights on the top, evenly distributed, to make sure the wing sits correctly in the bottom schuck. Keep in mind, just like with weights it's dire important to have a FLAT building surface. It doesn't take a lot of weight, just enough to push the wing flat into the bottom shuck.

Another tip I'd mention is to only leave about a 1/4 to 3/8" overhang. This is again why you want to have a mark to make sure the sheets are on correctly.

Hope this helps.

..............Mark

Kent,
You can find Procraft's phone number in Model Aviation, he didn't have a web site when I purchased the plans, cowl, canopy and wheel pants from him, he may have one now. The plans as drawn had a lot of parts, I redesigned to eliminate parts count. I cut the cores, that's another picture story.
Tony Hallo

Well get on with the pictures then.

Hey thanks to you all taking the time to share all this info as it's giving me confidence I need!!

Thanks a lot guys

Tony,

I have a vacuum pump but not a regulator. Can you show me some pics of the regulator and pump setup?

Craig

Vacuum is controlled with the bleed valve shown on bottom of the pump, opening the valve bleeds air into the pump suction and lowers the vacuum. I heard ours who used this system, the vent hole plugged and crushed the core, I make sure the work area is clean, start with the valve wide open, slowly close until the bag begins to evacuate, once the bag begins pulling down, the vacuum will increase rapidly. I do check the vacuum occasionally while bagging. My valve was on the pump when I brought it but any small needle valve tee'd to atmosphere in the vacuum line between the pump and the bag with work just fine. I friend of mine bought an air operated vacuum pump from Harbor Freight for about $10.00, he controls the vacuum by regulating the air pressure, this pump isn't the most energy efficient method! My pump is rated at 1.5 amps so it runs for pennies an hour.
I use fuel line for hose and purchase tee's at the local auto parts for multiple projects.

Tony,

THis is awesome stuff. I tried to bag some plain balsa/glass sandwiches today and it worked great. I pulled about 15 inches of HG though (not sure of accuracy of pressure gauge). Did you say only go 5 or less with foam cores? Also, how do you keep the wrinkles in the drop cloth from causing problems?

Thanks a bunch,
Craig

When working with balsa skins, the wrinkles are never a problem for me, I buy the cheapest drop cloths, maybe 1 1/2 mil stuff, I would image thicker plastic sheet would cause impressions where wrinkled. My opinion is buy the cheapest bag and throw it away after one use. The bag is only keeping the air out, the atmosphere is doing the work, better and thicker bags just cost more.
Tony Hallo

Well, I started this thread because I was thinking about building something like a Carden Cuda. After talking to Dennis today, I think I'm just going to have a builder do it. I think i'm going to skip the Cuda and get an ARC Dalton 35% Extra 260. Apparently it is harder than it looks and I don't know anyone that can help me through it. Thanks for your answers though, hopefully someone benefited.

Here's a photo of typical wrinkles during bagging. This was one of the stabilizers with Plywood end caps attached.

It's only as hard as you make it, keep in mind this is only a hobby. I live in Pennnsylvania, maybe a seven month flying season, twelve month building season, who needs ARF's? Good luck with the 260.
Here's my latest build, a Frank Knoll 34% Christen Eagle, ZDZ 80, canister muffler, 8 months of pleasure.
Tony Hallo

Yeah, but I'll only have limited time to work on it a year and I'm just not sure about the entire thing. I've never cut parts out of a single piece of foam before and I'm not sure that I have someone that can do it. I'll make a phone call tomorrow and see if I can't work something out. But, I just don't have access to someone with the knowledge I might need to help me.

My recommendation is go for it and have fun, if you make a mistake, learn from it and go on. Foam and balsa is cheap, mistakes can be fixed. My friend with the air powered vacuum pump has the Cuda with a FPE 3.2 & canister muffler, it's a good flying plane. We ever tried the air powered pump on his cores. The instructions provided with the Cuda will guide you along without any problem. Worst case, post another thread, good conversation, better than most of the posts here like, DA or 3W, Hitec vs JR.
Good Luck
Tony Hallo

Well, I'm going to call Max Blose (father of Todd Blose) on Thursday and see what he says. He's pretty much been giving me advice ever since I started and he'll give me an honest answer. On the plus side, he may even offer to help me do it. I'm not giving up yet, but I am going to explore all possibilities. I'd really like to do it all myself, but if need be I can hopefully find someone to do the parts I can't. Framing up that big fuse should be fun though.

If you are determined to start learning vacuum bagging -- read up on relative pressures and how to read them
also pressures allowable for white 1 lb foam - about 2 PSI (not water or mercury -)air is about right - there is lots to learn - keep edges all close to foam -no overhang -it will smash -
also if the foam blocks are not right - your product will be warped ,bowed or twisted - but if you read up you can do the first one OK
Frankly, the clamp is far easier -if you have a clamp---
Once you get by the first go around the next few hundred will go easier ---

Ok, I talked to Max Blose this morning about it and i'm going to build the Dalton Extra 260 all myself. Of course, I'm going to be doing this at my parents house in Texas since that's where all of my dad's fancy tools are and since I can get Max's help if I need it. All I need to do now is sell my Wild Hare Ultimate.

I posted some foam cutting information in the Tips and Techniques Forum, check it out.
Tony Hallo

Thanks, I bookmarked it. Lucky for me I don't have to cut the foam cores out, I just have to cut out the servo bays and then cut out the control surfaces. I like your jig, that's pretty neat. I plan on making something like that to use for the servo bays. As far as the cutting out the control surfaces, I'm going to take it down to Waco and get Max Blose to help me with the ailerons and then I'll probably do the rudder and elevator at my parents house. I'm going to be bulding this in my hometown since that's where all of my dad's fancy tools are. He has a bandsaw that has diamonds on the side of the blade for removing small amounts of wood that the blade missed. Plus he used to be a cabinet maker and an extra set of eyes are always good.

Tony, where do you get balsa like this:

Or is it several pieces glued together? Lonestar balsa has 12" wide pieces, but they are like 7 dollars, so a set of my jet wings would be 50 bucks or something like that.

Hi Tony,

Can you show us your jig for cutting cylindrical shapes such as turtledecks?