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forgive another glue question, but need advice

Hello, I'm about to assemble my 1st LOC kit (an Onyx). I was all set to use carpenter's wood glue when I read in the instructions that LOC wants me to use epoxy. I was under the belief that the body tube would tear and the fin would break before the yellow glue joint failed, and that since it soaks into the fiber that it would likely hold the surface mounted fins better than epoxy. Am I correct in these assumptions? I am flying this kit stock, so the biggest engine I'm likely to ever use is a G80 (and most of the time F50, F25 and F20). Craig

Reply to
Craig
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Craig, you will be much happier with the results if you get some 15 minute epoxy from your local hobby shop and use that. Carpenter's glue is strong, but you will get better results long term with epoxy.

Reply to
Darrell D. Mobley

The Onyx is a cool rocket. Build it with epoxy. You'll be very happy with the results.

Reply to
Jim

Your belief is 100% correct. Yellow glue will be just as strong or stronger than any epoxy you might use for this rocket. As long as your rockets are made of paper and wood, there is no good reason to use epoxy.

Over a decade ago I built a Thoy Hornet with yellow glue, and have flown it on D, E, F, G, and even an H238 and it's fine. Something else will fail long before the yellow glue gives out. I built this rocket specifically to do an "L1" type flight on a yellow glue rocket. I suppose the next project should be to build a LOC Magnum or similar rocket and do an "L2" fligth with yellow glue.

Can you use epoxy for this rocket. Sure. A good epoxy like System-3, West, or Raka will do fine. But so will good old yellow glue.

Reply to
Bob Kaplow

Craig, The situation you describe certainly holds in the model rocket context. There, epoxy tends to bond to only the outer layer of a body tube. Model rocket fins attached with epoxy are therefore only as strong as the bond between the outer layer and the layer underneath. Some things are different in MPR/HPR.

First, although you are using cardboard and wood, it is not exactly the same material.

Secondly, although I am not familiar with the construction of the Onyx, it is common for MPR rocket fins to insert into holes in a thick body tube. These holes drill though the layers of cardboard, so you don't have the outer-layer problem just described.

Thirdly, if there are holes, then the soundness of the fin-body bond is undermined by the shrinkage you get with water (or any solvent) based glues.

Hope that helps,

-Larry C.

Reply to
Larry Curcio

carpenters glue will do just fine, so will epoxy. Just because the manufacturer suggests epoxy does not make it the law.

Loc did not invent nor are they the gurus of adhesives.

Reply to
spiff

Just a follow up....I went ahead and built the model using white school glue.... . . . Just Kidding! Seriously, I used yellow glue for all but the shock cord mount, which was covered with a nice layer of 30 minute epoxy. I hope to fly it this weekend (paint should be well cured by then) and will let you all know how it holds up. I triple filleted the fins and engine mount, so it should hold up okay. Also sanded the body tube gloss off of where the fins and launch lug attached. Craig

Reply to
Craig

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