Jump to content

Vacuum bagging No8 Kiwi style


Recommended Posts

Just how the hell do you spell vacuum, it's different every spell checker I run into.... grrrrrrrr.


Helping a mate do some stuff in Aussie with this and as a few more local have asked I thought I'd chuck it up here.


Before I start please be aware -

- I am not a boat builder but I have built a couple.... plus one when this beast gets floating again.

- I am not a fibre glassing expert but I have used a fair amount of it.

- I've always used West System 105 or West ADR, bugger all else

- The shape I've used for this info piece is as simple as it gets so its as easy as it gets. Get into complex shapes and the game can change dramatically.

- The panels aren't large and certainly aren't the area of a TP52 for example.

- I'm using basic hardware shop gear but if you go to Cooksons, Lloyd Stevensons and those guys they use more application specific gear as they work at a level I can only dream about.


Some of the terminology could be off but I hope it's still understandable.


So I wanted some panels for my boat. I could have used ply but I wanted to transfer some weight around the boat so where I wanted these panels I needed lighter and stronger than where I added weight with ply. Hence I went composite.


I started with building a table on which to make the panels. This was made by scoring, for a 6 pack, a oversized sheet of 25mm MDF. I then added 50mm to each edge to make it 1300mm wide and I trimmed it at 3000mm long. There is a few 4x2's screwed underneith to make it stable and stay flat. I then coated the table with a grey mold paint stuff I think is called Duralax or very similar (Adhesive Technologies). That was sanded, coated again and sanded back smooth before using a proper release wax (Adhesive Tech again) to make sure nothing sticks to it. The table sits on some saw stools. Cost around $200 all up and I have paint and wax left over, which will get used on some other shapes I need to do.


I them got the foam that is to be the core. In this case it's 12mm 80kg/c (80 kilos per cubic metre) and cut it to the required size. In this case it was 2900mm x 450mm and I need 2 of them. As the foam is only 2100mm long I had to extend them. That was simply cutting the extra and using a wide masking tape sticking the 2 bits together on one side, the side that will be the bottom in the 1st suck. Foam from Adhesive Technologies.


In the photo you can see the 2 panels on the table cut to size and joined. One panel is face up (the left) and the other is the bottom showing the tape.post-646-141887269903.jpg

Then each panel got a slurry squeegee over it to fill all the micro holes in the foam. This slurry was resin with a hint of 411 power in it to give it a slight thickness. Spread in and around with a plastic 100mm blade (pack of 5 different sizes from Hammer Hardware for $1.99) that can be seen sitting on the blue container. post-646-141887269906.jpg

Next came the black shite, in this case I'm using 2 skins of 200gr plain carbon fibre (NZ Composites). This was pre cut to size prior to any resin being mixed. The eagle eyed out there will notice the carbon has joins, that's just me using up offcuts as these panels will be chopped up and not really load baring. As it panned out after a good sucking the overlaps are near invisible. Each layer got resin squeegeed over it.post-646-141887269909.jpg

Each panel got 2 layers of that carbon. After that came the peel ply, that's the white cloth you can see on the left panel. Peel ply (Adhesive technologies) is like spinnaker cloth (which I've been told also works well) and it's used to help take out a bit of excess resin and when you peel it off a nice ready to go minimal fecking sanding to be done finish. The head was intentionally removed from the ugly creature in the back left corner just in case any women or children see this thread ;)post-646-141887269912.jpg

Both panels with all the carbon down and peel ply on. The peel ply is sacrificial. You can see the resin coming thru in places.post-646-141887269916.jpg Now we are all done with the lamination part and are ready to get all sucky. Next I laid down a sheet of windbreak cloth (hammer hardware) so it covered all the panels. This is to allow the air to be sucked out from all over, it sneaks though all the tiny gaps in the windbreak. Some use shade cloth which also good. The pros have a range of flash stuff they can use. Once the windbreak is down I ran the sucky hose up between the panels. Some tape just to hold it in place. On the end of the hose is a bit of conduit I drilled full of holes and wrapped in windbreak so it wouldn't get clogged with resin should I have a massive brain fart. Thats got a few small bits of cloth over it to help the air find itpost-646-141887269919.jpg

Next we put down the sucky tape stuff. No idea what it is but it's like a fancy Blue Tac and a few mm thick to help get a good seal on the bag. The yellow colour is a high temperature version for when you suck and cook at the same time, which I'm not but we're doing some gear for a mates new skiff at the same time and his will be cooked as he's using the post cure ADR resin. The black is the normal stuff, I used both as a tribute to Wellington (??? :? ) You have to make sure the tape touches itself all the way around, any gap can lead to a hole and you get no sucky with holey.post-646-141887269922.jpg

Take some time where the tube goes in, a common spot for it to be a A Hole if it wants to be.post-646-141887269925.jpg

Next on goes the bag, in this case just a sheet of plastic I got from Hammer Hardware. I found it lasts about 2 to 3 sucks and then you need a new one. That goes over the lot and is held down by the sucky tape.post-646-141887269928.jpg This bit needs some detailed going over to make sure you have no gaps, even the smallest can cause a lack of vacuum.post-646-141887269931.jpg Once your happy the bag is down well then it's turn on the pump and see if your right time. In my case I was lucky enough to mention to Wheels I'd like a pump about the same time he spotted a major component on Trade Me. Wheels then used a old cigarette packet, the old fuel filter from his boat, 3 bananas, a few odds n ends and a Swiss Army knife to built this ripper of a machine. Cost around $120, which is spectacular as if you go to buy a small pump take over $1000 with you, probably a fair whack more. This pump has easily sucked the skin on a 14ft skiff and that entire table so it's working damn good.post-646-141887269933.jpg Turn the beast on and all going according to plan the bag will suck down. Ya Hoo!!!!! the bastard didpost-646-141887269937.jpg You can see the end of the sucky hose in the middle of the shot and how well everything packs down when under vacuumpost-646-14188726994.jpg Now you have to drink a few, generally a six pack person while your 'just checking it's holding not pressure'. Leave the whole thing sucking until the resin has gone off, in 20-25 degrees that's about 5-6 hours if you are using 105. It'll be cured enough you can be a little rough with it if you want to push 2 sides though in a day. I tend to suck in the morning, unpack in the evening and prep for the following morning where I laminate then get the sucker running before I head off to the office. Once the resins gone off we can take off the bag. This can be rip and dump or it can be careful for a reuse tomorrow (and being greener for the planet). It's pretty cheap (maybe $20 all up inc plastic and tape) so any hint of damage then dump it and get a new one. You can see in the photo a bit of the resin bleed into the windbreak cloth. I was somewhat enthusiastic with the resin on these 2 so it wasn't a surprise nor any concern.post-646-141887269942.jpg Strip off the windbreak cloth leaving just the peel ply.post-646-141887269945.jpg Then strip off the peel ply. This is easy just grab a corner and pull, not dissimilar to opening a tinny.... of beer that is.post-646-141887269948.jpg In this one you can see how the vacum has formed the carbon around a tight corner rather well. Also where the cloth got wetted out and where it didn't. A cool shot this onepost-646-141887269951.jpg Trim up the edges and if you are like me have plenty of plasters on hand, some of those edges make razors look blunt. Used 7 plasters to trim just one smaller panel, blood everywhere.post-646-141887270262.jpg Turn over and get into the other side.post-646-141887270265.jpg

I must say I'm happy with the results as the finished panels are all within sweet bugger all of the expected and calculated weight.


To do the above excluding the foam, carbon and resin - I'd say around $35 of the plastic, sucky tape and windbreak (Assuming you get 2-3 goes from each lot which wasn't hard but now I'd say maximum, I went twice then replace) and that also includes the peel ply per suck, so it's not to bad if you are doing a decent size or are using expensive materials.






Ahggg........ who stole all the photos??? sh*t!!!!

Phewwww, saved....

All fecking websites are evil.

Link to post
Share on other sites

Thanks IT. There are a few of us still out there doing it.


I like doing it, find it highly relaxing and like standing back at the end of the day and seeing something I've done/made/tweaked or sometimes made a total cock-up of. It's far better than the growing paper war that takes up a lot of my days.

Link to post
Share on other sites

The text is much better when the photos come up.


I have done some vacuuming only on small model parts and on the bigger pieces I put a layer of wadding between the peel ply and the bag.


3mm foam panels squeezed between 2 pieces on glass.




Link to post
Share on other sites

thanks for taking the time to post the; detailed procedures, materials, sources and pics


may it live long in posterity contributing to the diy database


of working the new black steel


so cool even jewelers use it



Link to post
Share on other sites

Good to see diy happening. A couple of tricks to save some time and money and eliminate the blood.


Roll a coat of resin on the table, hit it with a warm air gun to burst any air bubbles. All it has to do is seal the surface. Don't bother sanding, polishing or waxing it.

When cured cover it with thin plastic. Don't worry too much about folds or getting it perfectly smooth. The Bunnings painters drop sheet works well. 4 x 3m x 2m for $1. Lay peel ply over this.

Cut 2 pieces of cloth, one about 100mm bigger all round than the panel, one about 50mm less.

Drill 1mm holes every 50 mm or so in both directions in the foam (Stack the sheets up and use a sharpened piece of #8 as the drill bit, although a piece of thinner, high tensile wire works better.).

Lay up the bigger piece of carbon on the peel ply. Use extra resin on light laminates.

Lay the foam on top. No need for the bog, the vacuum will suck the air out and excess resin will replace it.

Fold the overlap over the edge of the foam and onto the top surface. Trim the corners if you want to make it look pretty.

Lay the smaller piece of cloth on top and wet it out. Should be a 50mm (less the thickness of the core) overlap between the 2 layers.

Peel ply and bleeder on top.

Tape the bag in place, making sure the plastic is inside it and NOT between the tape and the table and the bag is against the edges of the core all the way round.

Do the sucky thing.

When cured, remove the peel ply which will also remove any folds from the plastic. Panel is ready to use.

One side is mould smooth and there is no edge treatment or trimming required. To get both sides mould smooth put a sheet of sticky plastic covered, perforated mdf over the peel ply, then the bleeder on top of that.


Be careful with ester resins, they may eat the plastic. They should also be left on the table for 24 hours and stored away from direct sunlight as they can shrink if exposed to uneven heat. Wait at least a week before gluing esters with epoxy.

Some peel ply is coated with silicone which remains on the job, making painting impossible. Either check it or use approved material.


To make it even easier, infuse it. With a bit of forethought and imagination, it is possible to eliminate grinding, fairing, secondary laminating and a lot of the boat building work like filleting and tabbing bulkheads, rebates and flanges round hatches and windows, the hatches themselves, hull/deck tabbing, holes for rudders and skin fittings, solids for fittings, extra laminate and/or no core where required, etc etc. No injuries, dust or getting sticky. And a perfect laminate.



Link to post
Share on other sites

That's a good addition to the thread racecharter.


I did ponder doing 2 sides at once but decided putting the holes thru the foam, as you described and do need to do, would add too much weight. I used that excuse to cover the fact I didn't think I was good enough to do both at once without flirting with Miss Cock-Up...... but :shh: don't tell anyone that, it may tarnish my rep as the bestest fibre glassing guru within a 10 to 15mts radius of my mancave :lol: :lol:


I didn't know that about the peel ply. I just grabbed some from Adhesive. I may check that as it could piss with further bonding and I don't need that.


About to fit the new motor and suck down the engine mounts for it this weekend. That'll be a fun change from flat panels. I'm told I don't need to but I have the pump so why not make sure the new stuff has got the best chance of sticking to the old that I can give it.


Did all the weight calcs on the new cockpit last night. Holy crap, it's no wonder some of the new beasts bob around like balloons, the new 35's would have to be quite a bit lighter than my old 30. I've made a few savings by decreasing the 1980's 5-6mm of choppy skin to a 2000 1-2mm black/gold skin. But with some of the new gear/systems going in I'm expecting to go splash at close as the same weight she was when she came out. I had to remove weight and open room up or I risk sinking under the weight of and not having enough room to safely fit all the Cat 1 gear we have to carry, it's quite a bizarre situation really. I should have registered her overseas, it would have saved a lot of time and money.

Link to post
Share on other sites

I've come to the conclusion that if you are going to No8 some of this vacuum bagging it's better to use shade cloth than wind break cloth. Better still would be the real McCoy.


When sucking firmish the wet laminate is held down pretty damn firmly so anything on to of it can easily leave an imprint. Some panels have a mark where the suck hose was sitting on them, you'd have to have them pointed to you but they are there. I was using shade cloth as the air bleed layer, the layer that allows the trapped air to get to where the suck is happening so you get a even suck across the whole area you are doing. But the shade cloth is a little stiff so in some tricky places it was an arse to get to sit nicely so I tried some lot floppier Wind beak cloth. It worked well so I've stuck with it mostly.


But now I'm into the finishing I've noticed when I use the wind break it leaves a far bigger pattern in the face of the cured laminate as opposed to the finer weave shade cloth. While this isn't a biggie in most places it would be if I wanted to clear finish or get a super fine big free face.  Also I think I'll use a bit more bog now due to the greater pattern to hide, it'll be bugger all but it's still unwanted weight that won't have to be there if I knew to use a differing material for the bleed layer.


So a note to say just think about the bleed layer you use with regards to the finish you want. If you want mirror flat to clear finish I'd suggest staying away from wind break cloth for sure and use shade cloth or better still splurge and buy some of the real stuff. Adhesive Technologies have it, no idea what the price is.

Link to post
Share on other sites

When I bought foam from Gurit they drilled it for me. Much easier but you do need to lay up both sides in the same session. They will also cut panels in what ever pattern needed.

Link to post
Share on other sites

When I bought foam from Gurit they drilled it for me. Much easier but you do need to lay up both sides in the same session. They will also cut panels in what ever pattern needed.

Depends on how you do it and the time you have. One side at a time is lighter ;)


And if you make panels then cut your own you can pop out to the shed Monday morning for a quick anchor locker hatch build to find a handy offcut sitting there.


Not that I'm being super fussy but I do like my new hatch at 405 grams as it 10 times gruntier than the 665 gram one it replaced. I just re-read that and thought 'You anal bastard' :D


Dyneema hinging utilised on this hatch as well.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...