72 Combat Dunstall Clone

I have been so busy with the 650SS engine and hubs that I haven't had much time for the Commando.

I dropped the last of the 650 parts off at the machine shop and picked up the finished Frame Loop gussets.


They did a good job and the fit is perfect. I have 4 more pairs if anyone is interested. I had to have 10 made to get the price right. Time to tear it all down weld up the gussets and get ready for powder coat.

Stopped by the boat supply place and picked up some fiberglass supplies to fix the seat pan.


Yesterday I ground out all the bad glass and cracks in the gelcoat and am ready to lay it all back up in the morning.

I question the Combat status. I bought a 72 Combat new and still have it. The Combat came with black barrels (nobody would paint them silver) :? , 932 carbs, high compression head, disc brake, and a hotter cam, I believe a 2S cam.

mglemans said:

I question the Combat status. I bought a 72 Combat new and still have it. The Combat came with black barrels (nobody would paint them silver) :? , 932 carbs, high compression head, disc brake, and a hotter cam, I believe a 2S cam.

Click to expand...

Yes you are correct .040 decked off the Barrels (note the distance between the top fin on the jug and the first fin on the head, this gave a 10:1 compression ratio, and also a C is stamped on the head just under the head steady, This one has had the barrels painted silver but has the C on the head.

This is a great town to get fiberglass repaired or learn to do it your self. All the major boat builders had factories here until the economy took a dump. Christ craft, Wellcraft and several others have closed their doors in recent years, so there are lots of supply houses and Glass workers looking for work. I have several friends that have taught me a few things about working fiberglass and they are always ready to give a hand.

When making repairs to fiberglass there is a 6 to 1 rule, meaning that the repaired area should be 6 times the size as the damaged area. Most of my holes were 1/8 inch so the repaired area needed to be 3/4 in diameter when able. The repair should be feathered from the center out to the edge with the center remaining material being about 1/16 thick, and several layer of glass matt in progressively larger sizes used to fill the concave area. For most of the repairs that wasn't a problem but the entire back edge was only 1/16 inch to start with so I will have to do the repair is stages; first thicken the inside and stiffen it up considerably then finish the repairs on the out side followed by a coat of gelcoat.

First 2 rounds of Glass laid on the seat, first I plugged the holes from the top with 2 layers of mat with the second at least twice as large as the first, and let sit for an hour to cure. Then I turned it over and repeted the process followed by large strips of Diagonally sewn woven matt to add stiffness to the back and bottom sides that had the most repairs.





I added horizontal stiffing strips and a second layer of Diagonally sewn woven matt to the back to stiffen it up and set in the sun for a few hours to bake

Later after it all has set up Ill clean up the edges and start on the repairs on the back end.

After sitting in the sun for a few hours I cleaned up the sharp edges and set the seat back on the bike to check the fit one last time. I din't like the way it sat off center and had a fore and aft rock to it. and the seat touched the tank on the RT side and had an 1/8 inch gap on the other.



First I groung down the high spots in the glass to fit on the frame better.

]

I then rapped the frame loop in cellophane and put the seat back on and clamped it into the position I liked. I then mixed up some Duraglass body filler and packed it in the gap between the frame loop and the seat. and along the back end of the loop.







After the Duraglass set I pulled off the seat and cleaned up the edges and gave it a test fit Perfect fit no rocking no sliding.. solid as a rock!




Next I mixed up some resin and started glassing them in, more pics of the progress to come tomorrow.

This seems to me to be the difference between a restoration and a "resurrection".
GREAT work, Caferider.

pvisseriii said:

This seems to me to be the difference between a restoration and a "resurrection".
GREAT work, Caferider.

Click to expand...

Resurrection in deed!

I think it has held up pretty good for 35 year old fiberglass, that was thin from the beginning for racing.

Last night I laid glass on the seat blocks and this morning early I cleaned them up and laid a second layer of glass. after it set up I sanded it all down and tested the fit.



Sanded the top down and its ready for a coat of gelcoat.


Next I ground out the spider cracks from the back to prevent them from coming back, and prepped the back end for a layer of glass and then it all will get a coat of gelcoat.



After lunch its back to final glass repair.

Can you put a coat of gelcoat and get it to look smooth? I thought gelcoat was used as a mould release.

Jean

Jeandr said:

Can you put a coat of gelcoat and get it to look smooth? I thought gelcoat was used as a mould release.

Jean

Click to expand...

Yes, you can spray gelcoat .....thats how they are made to begin with. Fiberglass will hold 30 % its weight in water, not good if you want to make anything waterproof, the gelcoat is impervious to water. The gelcoat is usually sprayed over the mold release agent which could be Wax or Polyvinyl Alcohol (PVA) or both to a thickness of .010 -.030 thick, and then the Glass is laid over that once it has set up a little.

Even thinned with 5% Acetone the gelcoat is still a little thick and the gun needs to have the appropriate needle. You can pick up a HVLP gelcoat gun for $70 and up, most production guns use the same mixing cup to spray from to cut down on clean up.

I will spray on my final coat of Gelcoat for a smooth shiny finish.

Final Glass repaired on the back side sanded and prepped.





I used Cabosil powder to thicken the gelcoat so it wont run off vertical surfaces and spreads like body filler. I spread a thickened coat over all the repaired areas and started blocking it out.









Next is more blocking and gelcoat filler and Repeat, then final wet sanding and spray a coat of Gelcoat.

If you live near a Surf board shop, They have what is called "clear sanding resin" that sands down very easily. Its great for getting fiberglas work really smooth prior to the finish coat.

Bruce MacGregor said:

If you live near a Surf board shop, They have what is called "clear sanding resin" that sands down very easily. Its great for getting fiberglas work really smooth prior to the finish coat.

Click to expand...

I'm going to the Fiberglass shop this afternoon and Ill ask about it. Thanks. I know that there a lot of additives that make the build up of gelcoat and sanding easier thats why I added the Cabisol powder to the gelcoat.

After several coats of gelcoat and block sanding yesterday and blocking with 400 grit wet sandpaper this morning it is just about ready for the top coat of gelcoat.


I laid up the last round of gelcoat and will block and wet sand again and hopefully spray on the final gelcoat tonight before the weather changes.



It's off to the Fiberglass shop to get supplies and a new gelcoat gun for the spraying.

I'm reading this with great interest, Caferider. I have an extra Dunstall seat & pan that I want to modify into a solo setup. Great thread and pics!!!

cmessenk said:

I'm reading this with great interest, Caferider. I have an extra Dunstall seat & pan that I want to modify into a solo setup. Great thread and pics!!!

Click to expand...

Lets get together and make a mold of the original first then rebuild it as a solo seat. I'm getting the release agents right after this to make a seat pan that will fit perfectly so I can take off the pad with out messing with the seat to get to the center mount oil filler, after that I'm making a mold of this seat.

If you are doing it 'kind of on the cheap' brown, or clear for that matter packaging tape (50mm wide plastic kind of tape for closing boxes) makes quite good mold release. The only tricky part is getting it on without wrinkles, a better although much more expensive option is a teflon tape that has a fiberglass weave in it, it is nicer to use but its big benefit is that it is high temp so you can use it in an autoclave which you wont be doing Im guessing.

Cheesy said:

If you are doing it 'kind of on the cheap' brown, or clear for that matter packaging tape (50mm wide plastic kind of tape for closing boxes) makes quite good mold release. The only tricky part is getting it on without wrinkles, a better although much more expensive option is a teflon tape that has a fiberglass weave in it, it is nicer to use but its big benefit is that it is high temp so you can use it in an autoclave which you wont be doing Im guessing.

Click to expand...

Can't you just use Vaseline for a mold release?

Aerosol is the way to go. No brush marks etc.
http://cgi.ebay.com/18-oz-Mold-rele...067?pt=LH_DefaultDomain_0&hash=item4156802d7b

I got some goodies at the Fiberglass supply.
Mold release wax and PVA And a production Spray gun , it will spray Gelcoat and I also got the nozzle to spray the PVA. the great thing is you can use a paper cup and toss it when you are done and no mess to clean up except the nozzel.



I saw this 11 inch sanding block and thought I had better get it, What a mistake that thing kicked my A$$ wet sanding with a 11 inch block will flat out wear you out. Needless to say I didn't get to spray on the gelcoat but in the morning if the weather is good. I thought that I had it pretty straight using the standard 4 inch block boy was I wrong this thing was cutting long wide and showing every mistake I made.


Crooked as can be

Its streight now!

Not much work done on the seat this week the weather was too cold and wet to finish it. Rain and low 60s is not good

I did shoot a coat of gelcoat before it started to rain, it had a bunch of pinholes that sucked up the gelcoat and didn't come out slick so I had to block it out one more time. Once the weather warms up Ill get back to it and shoot another coat.
here is a pic of the seat in the sun warming up before I could shoot the gelcoat.

I may prep it with wax and PVA to make a mold from it and then degrease it and block and shoot a coat of DP90 on it and set it aside for the paint shop.



While it was raining, I did manage to get to work on the wheels. I Stripped the anodizing from the rims and polished the front disc hub, cut the spokes out of the rear wheel and started on the hub. Not that I can see why but, is anyone interested in a 16 5 40 spoke rim? The chrome is in good condition.