plug making

I am looking into building a male plug by attaching large flat panels to a wooden framework of transverse bulkheads( supported longitudinally as well).The thought is to lay up gelcoat/glass and perhaps a thin core on a flat table to get large fair sections,and reduce the fairing work to attachment and transition points.does anybody have any ideas on surfacing the table(formica,melamine etc),layup schedule to get a skin rigid enoug to make a mold fro,yet flexible enough to bend into cuves?

 

I have used Airex to construct flat (sort of ) pannels for coach roofs and large decks.

If the glass is laid up on only one surface of the airex , even a 1/4 inch laminate will take a good bend WHEN GREEN!

"Green "is with in a day or two of lay up when the GRP will still flex easily .

The outer surface is then laid on , but fairing IS required to finish nicely.

Does this help?

FAST FRED

 

Client of mine did something similar as you want to do with the plug I drew for him. He used 1/8" ply and sealed faired it out before installing it.

He said the end result saved him some time, but not much.

 

Both fast fred and jem replies appreciated.What I am trying to accomplish is a smooth surface on the bottom of panel...gelcoat/glass/core.Then attaching it framing/core/glass/gelcoat on the outer suface.Then glassing the inside of the core to stiffen once the somewhat flexible outer skin has been attached.

 

Couple of concerns...and I'm not sure how big or little an issue this might be.

By doing it in the manner you described, you're relying on the panel to bend and shape in exactly the same manner on both mirrored halves of the hull. You may be better off using more internal frames for the plug to ensure you have the curvature you desire.

This depends a lot on the dimensions of your panels. On the 17' x 5' plug I designed for my Texas client, we used interlocking frames spaced every 18". For his surface, he used 1/4" (6mm) plywood and put the finished side facing out.

To attach, he predrilled and counter sunk drywall screws to reduce the chance of dimpling (is that a word :?: ) from the screw heads pulling on the surface of the hull skin.

Once everything was lined up and looked good, he then glued (fillet and tape) the frames to the plug from the inside. That part was time consuming.

Once everything was glued and cured, he removed the screws and filled in the holes. I think some finishing nails could have achieved the same results as the screws without having to remove them later. But screws were the better choice in case the panels had to be adjusted on the frames.

After that, it was a lot of bondo, a lot of sanding, and a lot patience. I beleive he finished everything off with Duretec and buffing. Plug is on it's way to the Mexican plant for mold construction starting on Nov 29th. Can't wait to hear how it turned out because I have a plug a client in CA wants me to make.

 

JEM-EMAIL ME gasdok007@earthlink.net re what type of services you provide.

 

done.

 

you can use formica that is used for shower surrounds to make a plug. the main problem is going to be laminating the sheets to the structure underneath smoothly. right now i am building a mold for a 12 pirouge i have made a frame from 1x4 set on 2-4x6 then put a layer of 1/8 plywood on the sides and am about to start cvering the plywood with formica. I am only going to use this mold once to make a decent plug from which i can make a production mold. I did a test sample on the formica, i cleaned the formica with acetone the coated it with a layer of chopped mat, The layup released great from the formica even with no gelcoat or waxing. Keep in mind that this mold will only be used once to make a plug that can be worked to make the final mold. from what i understand modeling clay can be used in the tight spots to make the joints, corners, ect come out round or smooth. just though you might be able to use this info, does anyone have any better ideas or suggestions for what i'm doing?

 

I have been researching this issue and , if you are not making compound curves, a flat panel lay up is the way to go. Lay up flat panels on a flat table formica or solid surface- gelcoat, thin layer of glass-very flexible.Or better yet- buy the panels they use to make RV bodies- They are available up to 102 inches wide in 250 ft long rolls.Imagine- no fairing of the plug.I cant remember the source of the top of my head, but its somewhere in my shop,and I can find it if you like. Check out www.kellsall.com- kiwi guy builds finished boats out of flat panels.

 

gasdok007, This RV material sounds interesting, does it work the same way as formica sheets for tub surrounds? if you come across the information on it and its not too much trouble send me a copy, phillipeit@cox.net I also tried the link that you had on your last post, but it came up not found is it correct? Thanks Phillip

Oh yeah, another little trick that I heard was to use modeling clay to smooth tight corners and joints, I friend told me that the gelcoat will release from the modeling clay, ever heard of this? it would give you a little more flexability as far as designing curves.
when i finish this pirouge mold, I'm thinking about using the same idea to build a large flatboat for a crabboat, probably 24-28 ft, I think I might go with a mold out of formica that I can just use once for the boat, I think it would beat all the fairing of building it out of plywwod and fiberglass or something like c-flex. The boat wouldn't have any major curves, (just a functunal work boat) so I'm thinking that this might be the way to go. what yall think?

 

I'm finishing up one of those Kiwi guys boats and your correct that this is the only way to build a fair mold easily. My poject is a 40' cat but another builder down the road used a similar table to build a hard chine 72' motor yacht. Nice part is he sold the proto after taking a mold. I have a site where we post pictures. Thing is its a free site and I'm only allowed so much bandwidth. So if the site says you cant get there from here. Just wait awhile and they'll reload.
http://www.geocities.com/TheTropics/Shores/1748/

 

I am closing down my boat company would you be interested in the plugs and molds?

Jay
compassboats.com
956-237-8075