View Full Version : cold molding barrelback 19

twisted laminator
04-18-2010, 09:02 AM
ready for second layer of 4mm okuome. using systems 3 general purpose laminating resin. for first layer i applied non thickened to frames and beveled plank edges, then thickened w/ wood flour, re-applied and fastened. i'm thinking i can roll hull and back of plank laminations w/ non thickened and not need thickened coat cuz i'm gonna vac bag( poly and duct tape or double backed). any thoughts. thanks

Bob Perkins
04-18-2010, 09:11 AM
I'm not sure I understand your question.. However - I vacuum bagged my hull. Same construction.

Look here: http://biscayne22.shutterfly.com (http://biscayne22.shutterfly.com/)


twisted laminator
04-18-2010, 09:33 AM
you're the guy inspiring me to vac bag. i've admired your runabout and it's construction. my question is whether i need to thicken lam resin, or not. assume reasonable fairness in hull after first layer. if i was not bagging i would think i'd need to thicken between layers for gap filling, since there will be some degree of gap between fasteners(staples). with bagging i'm thinking no thickening required since lams will be so tight? what glue did you use for cold molding? thank you

04-18-2010, 10:45 AM
I'm interested in this answer myself

Bob Perkins
04-19-2010, 09:26 AM
Hi -
After the first layer - I skim coated the hull with epoxy and sandable filler (micro balloons) to fill any holes and the seams, etc.. I faired the hull here too.

when I laminated - I used System 3 epoxy (because I could get it at a major discount at the time). I used filler (silica) to get the epoxy to a mayonnaise of softer consistency. It needs to stay in place and not drip down the hull.

I spread it with a 1/8" v-notch spreader. West System has one. and combed it out. You do not need excess epoxy.

This picture:
http://im1.shutterfly.com/media/47b7d727b3127ccec2580daee3f500000010O00AZt2TFi5bt2 IPbz4E/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/
Shows the glue lines - they are very thin and tight. Vacuum did an outstanding job here.

I wanted the glue to be liquid enough to spread easily, but not sag and drip.

Hope this helps,

twisted laminator
04-19-2010, 03:58 PM
thanks very much Bob. can i ask you a question or two regarding your shutterfly photo "first section of bottom bagged"? is that duct tape at perimeter of poly? what is white material and it's function? is it a platen or a cushion to protect 6 mil from plank edges. i do alot of bagging with polyurethane bags and haven't really tried relatively thin polyethylene sheet. thanks again.

Bob Perkins
04-19-2010, 04:14 PM
My order or work was something like this:

Precut and prefit next layer of planking - tack in place with a staple or two. I carried the batten lines in pencil to the outside. I wanted to always staple into solid wood and not have them blow through on the other side.

When you have your planks in place
Precut and pretape the covering plastic on the top edge and fold it back.

There are two layers of white stuff. The first that goes directly over the planking is peel ply. It is essentially very slick 100% polyester fabric. Instead of purchasing marine peel ply - I went to Joanne fabrics and purchased the same stuff - is is dress lining... very inexpensive - and JoAnn often has 40% off coupons.

The next layer is quilt batting - or in marine terms - breather fabric. The breather allows the air to escape and not get trapped in a bubble. You can use plastic window screen for this also.

Peel ply allows you to peel all of this off of the lamination once dry. also - any excess epoxy squeeze out will pass through the fabric. so no potential lumps...

when it is all precut and ready to go - I peel it all off, spread the glue and put it all back - tape around the edges and apply vacuum.

The poly sheeting does not stick to the duct tape very well - however the vacuum helps to seal it. Then use plain old clay to plug any leaks.

best advice - biggest vacuum pump possible - I wish I had 10CFM at minimum - and a long hose to put the pump out of earshot so you can hear leaks.

Once you get the hang of it , it is simple.. You could bag with plastic wrap as long as you pleated properly - so thickness is not too too important. Start with small sections until you get the hang of it. Working the sheer is the toughest part.

Hope this helps

Bob Perkins
04-19-2010, 04:39 PM
missed this answer: yes - it is duct tape - 3M gorilla I believe- The heavy duty super stick stuff.. not dollar store tape - that would not stick..

twisted laminator
04-19-2010, 09:02 PM
much appreciate. should be great help. thanks