What glue to use?

[jbrase2000]

I've started building a Dumas Chris-Craft boat - my first attempt at R/C boating.

This is probably a big project for a beginner, but I'm into it now and have no intention of giving up. But, I'll probably have a lot of seemingly stupid questions as I go along.

The first one has to do with glue. The instructions indicate that I need, "thin and thick CyA glue" and, "Epoxy Cement." Ok, I've got all three. But then I come to the place in the instructions where it says something like, "cement these parts together." It doesn't tell me which glue to use. How do I know? Can I assume that "cement" means "Epoxy Cement" and "glue" means "Cya" or is that reading too much into the strict meaning of the words?

The parts in question at the moment are the keel to frame connections and the chine to frame connections.

TIA,
John

[Hydro Junkie]

A general rule of thumb is CA is used for frame assembly. Where the thick and thin come in is the thick's ability to fill gaps and thins ability to instant tack or whet(sp) into a seam. Where epoxy comes in is where you need strength and water resistance. Not sure what kind of skin comes with your boat, so I'm going to try and "wing it". If the skin is a plywood, use epoxy to attach it to the framing. Be sure to use lots of clamps/tape/pins to hold it in place. For waterproofing, coat the entire panel on the inside of the hull, as well as the framing. If the skin is plank on frame, use CA to hold the planks in place. When you get the hull completed, coat the inside with epoxy, both for srength and waterproofing. Hope this gets you started. Something else you might do is contact your LHS(local hobby shop for short) and see if there is a scale boat club in the area. Not knowing where you're located makes it hard to recommend any further than that.

[jbrase2000]

Thanks for the quick and helpful response.

This boat has a planked hull. (Well, it will have when I get that far.) The frames, keel, stringers and such are all in place and today, chores and football permitting, I'll start on the sub-planking.

You suggest coating the inside of the hull with epoxy. What type, consistency, (brand?) do you recommend? I have several spray guns so if there is something "sprayable" I'm thinking that might be a nifty application method.

To answer your other question, I'm near Indianapolis. There is an R/C sailboat club in the area but so far I've not found any power boat guys and the two local hobby shops seem a little weak on boat stuff.

John

[Hydro Junkie]

I prefer West Systems myself. They have a full line of products based on one resin. They have three or four hardeners, fillers, thickeners and who knows what all else. It's spendy stuff, but for marine use, I wouldn't buy anything else. Don't know if it can be sprayed or not, but I've been told to add some acetone or alcohol in as a thinner for coating hulls as a prepaint sealer. Haven't done it yet, but I'm looking at that for my present project.

If I remember right, there is at least one guy at Fort Wayne on the site, don't remember which guy.

Back to the West Systems, it can be purchased at most marine supply houses.

[Doc]

John,
I don't think I've ever seen epoxy sprayed before (not saying it can't be done, just never heard of anyone doing it). Another method is to thin it down and paint it on with a brush (or in case of a 'small' hull, pour it in, slosh it around, dump the excess out, clean up the mess! lol). The same can be done with a 'polyurethane'(sp) varnish on the inside of the hull. But not the outside, painting over it is a problem!
Hope this helps...
- 'Doc

[jbrase2000]

Doc,
What do you use to thin the epoxy? My first guess would be acetone but I'm not sure on this. I'd also guess that you'd need to add the thinner to the resin before adding the hardener but that leaves me to wonder if doing so would change the resin/hardener ratio.

Progress Report: I managed to grab a few hours away from chores and TV sports over the weekend to work on the boat. I finished the framework and started laying the subplanking. It is slow going work. The planks go on at a 45 degree angle to the keel which requires a lot of cutting and trimming of a lot of little pieces of plywood. I do have the advantage of having a fully equipped woodworking shop to work in. Cutting 2" long strips of ply on a full sized 3hp table saw might seem like overkill, though.

John

[Doc]

John,
The most common(?) thinner used with epoxy is alcohol (rubbing, not drinking). I haven't tried it but acetone should work, I'd think. Mix up the two components, then dilute with the thinner (works for me). Use about 30%, or the same amount of thinner as either of the two 'parts' of the epoxy. I would also recommend using the 'slow' setting epoxy, not the 'fast' stuff. (The 'fast' stuff isn't exactly water proof, the 'slow' stuff is.) I'd also recommend doing a test batch before working on the boat! Different brands of epoxy ~can~ react differently.

There's an alternative, but you do have to be careful with it, and it isn't suitable for all boats. Instead of planking with epoxy/wood glue, use CA. Sand smooth then apply some form of 'plastic wood' (dilutes with water so can be brushed on) to the whole hull. Start sanding again. Then coat with epoxy paint. Count on ~lots~ of sanding! This will give you a slightly heavy hull (depends on how much sanding) and the grain of the wood does NOT show through (wouldn't be my first choice for the Dumas boat, but it's an alternative).
Good luck...
- 'Doc

[Scott Richard]

John, I am have built the same boat dumas chris craft barrel back.I have also ran into this same problem I started to use expoxy on the whole boat untill a friend brought light into my face, by saying that it will ride very low in the water becasue of the weight of expoxy. I was also worried about the lean from right to left while sitting in the water. Becasue I coated the inside of the boat with expoxy and a paint brush so that water would puddle up instead of soak ing the wood. All of this was not effective as I thought after the boat was complete. My boat sits perfect on the water with no added weight and two 6cell battery packs. This was also my first boat building attempt. It took me a little more than 4 years to complete but I was on and off of the project throughtout the years. (I also graduated college during the same time) After all the problems I have ran into, the kit is set up very well in the areas of planning and material.

I would have to go with Cya glue because with this boat as you will run into has many tight pecies that have to be twisted and shaped into its position which expoxy takes too long to setup. As with cya it sets very fast almost too fast. Let me know how things are going of the woodie.

scott richard

[jbrase2000]

Scott,
>>Let me know how things are going of the woodie.<<

Looks like we have two threads going... Anyway, I am at the point where the hull planking is done and the deck planking is next. You are right, there are places where the mahogany has to be forced into unnatural twists and turns. I ended up in the kitchen using my wife's steamer pot to steam some of the planks before trying to bend them into shape. She didn't like it much but it worked beautifully. If you don't mind the burning sensation in your fingertips. Speaking of which, I think I've glued myself to the boat about a hundred times so far. I've also figured out that good quality masking tape, streached tight, makes an excellent "clamp" for places where no other clamp will work.

I did end up brushing thin epoxy on the inside of the hull. I found a product at one of the big box hardware stores that was thin out of the can so that problem turned out to be no problem at all. I may use the same stuff on the outside as well. I'm still undecided whether I should use fiberglass cloth with the epoxy on the hull. It seems like overkill at this point. This boat seems plenty strong as it is.

My interest in old woodies goes back to my youth and visits to Grandad's lake cottage. The rich folks on the other side of the lake had Chris Crafts and I always loved the way those boats looked and sounded.

John

[scorpien boats]

I've started building a Dumas Chris-Craft boat - my first attempt at R/C boating.

This is probably a big project for a beginner, but I'm into it now and have no intention of giving up. But, I'll probably have a lot of seemingly stupid questions as I go along.

The first one has to do with glue. The instructions indicate that I need, "thin and thick CyA glue" and, "Epoxy Cement." Ok, I've got all three. But then I come to the place in the instructions where it says something like, "cement these parts together." It doesn't tell me which glue to use. How do I know? Can I assume that "cement" means "Epoxy Cement" and "glue" means "Cya" or is that reading too much into the strict meaning of the words?

The parts in question at the moment are the keel to frame connections and the chine to frame connections.

TIA,
John

when i built my dumas boat they used cya for the abreviation...

[Doc]

scorpien',
"CYA" is what you do in case you need an 'excuse' - LOL! 'CA' is the industry 'standard'. Not really a problem either way, though...
- 'Doc