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Polymer, off w/ old on w/ new?

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Anezangl

Well-known member
Let me start by asking you guys not to laugh to hard at my question. I have been watching this site for quite some time and am slowly moving toward getting a airboat. My wife says I can have a turn key boat as soon as I relive myself of the boat that was my passion for the last 15 years. :) Nice of her huh? Anyway, until then I have deceided to tinker on building a small airboat myself just to see what I come up with. (Really, it's more about spending the time w/ my 12 year old son on "my " weekends. Something we can do together.) Just yesterday I was able to take possesion of an older hull, didn't cost much, just had to remove it from a ladies backyard. It is a aluminum, professionally built, 11' x 7' full deck, very good condition just needs cleaned up. My question is this........there are an awlful lot of what I call aircraft quality rivets holding the old polymer to the bottom of this hull! They are well placed and professional in apperence BUT, when removed how are all those holes sealed before the new sheet is applied? What am I missing? OK, stop laugh'n.....remember I'm new to this. :) Thanks for any info.
 
They typically are welded idf they are closed but if you drioll out the rivets typically you can re-rivet in the same holes.

That is a great project to undertake with your son, it will be a lot of work but very rewarding.
 
I shoot a short rivet to close all old holes.
Then start a new spread for the new polymer. This works. No problems!
The only other way is to weld old holes shut. Not the best way!
There is no way to properly install new poly using old holes, as poly continually changes as it heats up. You need to put poly on as hot as possible. Otherwise it will bag when hot ( dry running).

Grant
 
Grant, a few months or so before you started posting on here we had a thread about glueing poly on. Maybe a row of rivets across the bow and transom for security, but for the most part, nothing else between.

I've always campaigned that it's dang nigh criminal to build a new hull and then punch it full of holes to put a sheet of polymer on it. I also believe that if we can glue the tiles on the space shuttle, then we can surely glue a sheet of poly to an ol' airboat.

We just haven't figured it out how yet ....

olf
 
My polymere's way over due for replacement ,its cracked and has been revited in a couple of spots for safety reasons. If anybody hears good results regarding the gluing method please post it .

Not looking forward to replacing the sheet.
 
To remove the old rivets and polymer I make a HEAVY cutter out of 1/2 plaqte steel about 6" wide with a heavy pipe or solid handle. Get on the dumb end and go to work chopping off rivets with the smart end.

I just clean it up, lay on the new, let the sun heat it so it lays down, and drill the new polymer from inside the hull (upside down) and use the same holes. Never had any problems with this. Did a LOT of them that way in the seismic world. You need a couple good men to do it this way, it will be hard just you and your 12 YO son because of the constant allignment issues. Once it starts running off center its near impossible to get it back in line. It ends up with bubbles and blisters. Also backing up the rivets in side the hull with a heavy hammer or rivet bucking tool is hard, loud tiring work.

Hope it helps. Its HARD work.

Scotty
 
I've heard of screws used on polymere .
Any body else ever use or hear of someone using screws to attach poly?
 
My glass boats have had it screwed on. Its ugly inside but it does work. I have heard of it screwed on metal hulls too but never seen it.

Heres an idea. Since this is a project for you and your son to spend some time working together. Maybe just tape the holes on the inside then steelflex the outside. The steelflex should fill the holes and still seal everything up nicely. Never seen this done, just kinda thinking out loud here. I'm about 50/50 in my mind right now between steel flexing or polymer on my new boat.

I don't like polymer at all but I don't know of any alternative other than steelflex. (Slick Bottom, Frog Spit, etc.)

Scotty
 
robert4570":im03u2xb said:
My polymere's way over due for replacement ,its cracked and has been revited in a couple of spots for safety reasons. If anybody hears good results regarding the gluing method please post it .

Not looking forward to replacing the sheet.
Click to expand...
My concern with IF, you did find a good glue, how would you get it back off to replace it?
 
Anezangl,

Welcome to S.A.! Here's the thread Olf was speaking of:

http://www.southernairboat.com/phpBB2/v ... ht=polymer

My polymers screwed on with countersunk bolt heads. Lot more work yeah, but worth the sigh of relief when sliding around out there!

Basketcase

P.S. There's a lot more threads on polymer bonding/installation, (use the "search" engine feature at the top of the page on S.A.! :wink:
 
Anezangel,
Welcome aboard!
Sure glad you got that boat, and wishing you and your son the best of times working on it, and enjoying it.

All that said, I;m not sure of your abillity level. Perhaps your more than able to tackle that polymer replacement project. It will be a job.

Not sure what type of boat you got, but if it's a full deck glades type sled with skinny sides.... well some decking will probably be coming off also to replace the polymer. "access"

You might be better off to take it to a pro, and get it done. Just a suggestion.

Look at the posts by Robert above.
He's an experienced airboater, and he don't wanna fool with it!
I don't blame him.

It can be done by any determined individual with the right know-how and tools.
If you really want to, I'm sure you can.
Just make sure you know what your getting into.

You and your son get it done right, and you'll darned sure be able to ride with pride!
 
Anezangel,

Cowboy is right. I definitely don't like doing poly jobs. I still do my own and help a few friends also.
It is basically a half day job for 3 good men with the right equipment after the boat is stripped and rolled over. Bear in mind it has to be done in the sun, the hotter the better.
I really don't like going thru old holes, as they tend to get over sized and then require longer or larger rivets.

Grant
 
See my confusion? The hull is a full deck and I'm not real sure my son is small enough to get inside that small cavity and then allow me to beat on the hull to set rivets. I know he is smarter than that.......:) Olf, I do know that they make some very strong adhesives. I was on a project years back working w/ some 3M corp folks from the adhesive division. They had documents that show how the newer 737 wings are taped together! Double sided tape! They had samples and vidieo of testing. A few weeks later I was on a business trip, looked out the window of the 737 I was on and............there were no rivets in the wing surfaces! It was very un-nerving! Maybe I could cut some "Inspection panels" through the deck at cosmeticly correct places so that I can get at the back side of those rivets. Someone I work with suggested I fill in the old holes w/ an aluminum rod he has seen that you heat and apply with a benz-o-matic torch? Said it is like welding but without the TIG. You guys keep throwing the ideas at me we'll stumble over something sooner or later! Thanks!
 
If you can rivet, then take an airchisel, and demo off the shopheads for the rear deck. Then punch the rivets out.

Grant's advice for closing the holes with countersunk rivets ain't bad.
I'd probably just go with steelflex after that. "epoxy coating"

But I ain't you.

Grant is correct on the holes.
It has been done many times before to use the existing hole for the new polymer rivets. Some will undoubtably get oversized, and may leak some. Also may not be as strong as other rivets in the pattern.

If you go back with polymer, you'll need your boy to drill through the new sheet from the inside out.

Then you will return from the outside to countersink for the rivet 1/16th below flush with the polymer.

Then you'll be ready to fasten it.
 
You will never have problems with the rivets used for hole plugs, as they are not doing anything but plugging a hole.
Good point on the steelflex Cowboy, didn't think to say that as it is a given for me. Anytime there is bare aluminum involved always cover it with something, otherwise if you keep the boat long enough you will end up with corrosion.

Grant
 
Anezangl, i just did this not to long ago get a air chizel with a flat blade and goto work, then decide if you want to use poly again, if not counter sink then rivet holes then steel flex. be sure to just take out the rivets when using air chizel and not the bottom. also if you boat is made out of 7075t6 don't attempt to weld and if you going to use poly take old off tape up the holes on the inside so when you steelflex it won't run threw redrill old holes and rivet back on. i dony know if your familiar with this stuff but they are special sized drill bits for the aircraft rivets iam not at home so i can't give you the name and # of the place to order from but someone here i'm sure will help with that.
 
Cowboy, I don't know about my skill level either but.................my wife says my hands are a gift from God! Ha! :) Wonder what she means by that? Hey Grant & KR23, what is this steelflex, it sounds very tough if you can fill old holes and then drill them back out. I guess this is to keep the hole from being wobbled out? You say not to leave the aluminum raw because of the chance for corrosion, would this steelflex work good between the hull and polymer? I am conident that w/ help from all you great people here a SB my son and I will have a great time and be successful! Thanks for all you interest in us!
 
Anezangl,

Steelflex is just a heavy bodied epoxy swimming pool paint.
I always put it on the hull before riveting on the poly. It has been used for airboat bottom coating long before the advent of poly. There are many new, improved products out there now. Steelflex works and is relatively inexpensive.

Grant
 
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