And So it begins

[martin]

Vacuum bagging the Glass to the nida core just before the rain arrived. Two great friends helped me with the process.. My vacumm pump could not keep up with such a large area so we tried the shop vac

[martin]

vacumm baggin before the rain came. and not a moment to soon

[martin]

okay it has been a while.. I was wondering how I need to set my lines to layout the deck.. do I just lay a2x4 across the stringers and mark a line or do I need to level the boat and then uses a rotory laser level to shot the line... I have both just to let you know.. I am at odds on this.. I have all the materials to layout floor just have been at a stale mate on this.. the tops cap is installed and need to start with floor.. thanks

[martin]

Bump

[db3155]

bump I need to know also...

[JohnC]

Can you give a quick run-down of your vacuum bagging? I have almost no experience with bagging and I am curious how you use those materials.

[martin]

Originally Posted by JohnC

Can you give a quick run-down of your vacuum bagging? I have almost no experience with bagging and I am curious how you use those materials.

I will tell you what I know, which is by far not much...my bagging system is pretty basic.i use a 7.5 cfm yellow jacket two stage vac pump. Some use the Venturi pumps that you hook up to your compressor.. My compressor is not that big. So I use a my vac pump.. Any way bagging allows an equal force applied to all sides of your part you are building.. It helps with big and small parts... It also allows to be able to pull all the resin inbetween all layers of foam so that you end up with one solid piece. the object of vacuum bagging for me is to build a solid full cure part with no excess build up of resin. Trying to find the Correct resin to cloth ratio is the trick. After some practice at certain temps , you get and idea. Plus there is lost of knowledge on here for correct resin to mat ratio's..there is a lot of waste when it comes to bagging. So that is where I try to use less expensive materials.. Bagging film , peel ply , breather film, bag tape all can add up. So I use large bubblewrap from lowes and 6 mil visqen. And tacky tape for metal roofing...
I build a lay up table with melamine one side Mdf.. Box it then screw two together to ache I've an 8'x8' layup table.. Cut you part out from a pattern and lay on table.. Mark and outline the part. Then come out about 8" over size all the way around and lay a perimeter of 1/2" tape . Then on the outside of your tape lay down you tacky tape . Stick it to the tabl but do not pull the backing.. Leave it then take some 2" blue painters tape and cover the tacky tape... This is to protect the tacky tape from getting resin on it...this is your working area. Wax the hell out of the working area now. Usually two good polishings will work.You cut your visqen slightly large than the tacky tape. You will have to make gussets if the part is going to be thick..
After cut you visqen set asid.. Now you have your part cut from foam.you should drill some 1/8"bleeder holes to allow to pull resin through..take some 1.5 oz mat cut to size and two laywers of 17/08 cut to size.. Mix your resin wet out the mat first then wet (wait first you should have made a test batch of an 2 oz of resin and time it so that you have an idea as to what your working time is when it kicks off.
Now you have that. And after lots of practice. You will get a better feel. Now wet your mat out. Then 1708 and then 1708 again. Make sure the 08 csm side is against the foam..it allows a better contact adhesion to the foam..some say to pre coat the foam with resin ,to make a tack layer. But I don't.
Now set your pre drilled foam on then a layer of bubble wrap and your 1" pre cut and slit pvc pipe down .now pllace your visqen down over that. And start from one end and pull the tape off the tacky tape and seal the bag up.. After that is down cut a hole through the bag and pipe and push your tubing in then seal it off with tacky tape.. Start pulling a vac. Down to 25 then lett up to 18-20,,,, record the heat generated and cure time. You do not want to pull so much vac that you end up with a dry lam. Keep and eye on how much resin is pulled out of your part..once done and hard pull your part off the table .. Ship shape tv and west systems did a great show on this.. Check it out...

[martin]

I forgot to say lay one layer of glass first and let set up. While you are in the chemical bond window then add your two layers of 1708 and foam

[JohnC]

Thank you for the explanation. I will have to adapt it to my transom layup but I will make some smaller parts first as you suggest to get the hang of the materials. I need a few hatches so that's probable a good place to start.

[martin]

I used the same techniques on my 23. And for the hatches. All epoxy on transom.. And poly for hatches...I just re core them..vac bagging needs to be on a flat surface. Vertical bagging has not worked for.me cause I cannot keep my seal tape clean. I think rtm would be best.. Also use duct tape to help seal the bag..