Vac bagging Q's

General Discussion
1

Hey Guy

OK, been reading through the archive for hours now and can't really find what I'm looking for.

My surfboard building area has now gone to make room for an other project (EH holden rebuild) Still haven't found one yet.

But as usual, I am thinking of another board for myself.

Been looking at the vac bagging process.

Would like to do a balsa skinned decked board and have no problems understanding that technique.

But, can glassing the regularlly glassed parts of the process and any regularlly constructed board be done in a vac bag.

Well I am pretty sure it can but do you really need the peel ply and all the other expensive gear to go with it??

I am already building a vac pump from a fridge compressor as we speak and as I will now probablly only build 1 or 2 a year for myself, I dont want to spend if I dont need to.

Another plus for me being in a bag would be to eliminate any contaminants that are flying around as now my building area is a pretty windy spot in the garage.

I figure I can bag it and maybe even wrap it in an electric blanket to speed things up.

So basicly, can I bag a regularlly glassed board in just the bag?

Probablly should have asked that at the start.

Cheers

 

 

2

Hey mate,

 

There's a whole bunch of headaches and very little gain in vac bagging your outer glass. The pressure squashes laps down nice and tight, but creates pinholes you need to seal anyway.

A bagged glass still requires sanding and filler coat, every time. Guaranteed NO saving in any labour.

 

Put your skins on in a bag, but finish with a good normal glass job "En Plein Air!"

 

Josh

www.joshdowlingshape.com

 

 

3

mds,

IMHO it's overkill to bag normal laminates.  Best for materials that want expand when wet out such as Innegra, Xynole, and non-wovens.  You don't have to use peel ply but need to use at least a perforated release material between the laminate and the bleeder/breather.  I use 1mil with perforations spaced about 2.5mm.  You will need to sand after using the release film as it will leave a smooth surface.  Peel ply leaves a surface that is ready for bonding.  With thin laminates you would need to use the perforated release film over the peel ply to prevent the bleeder/breather from absorbing too much resin.  If you get it to work its pretty neat because the laps will come out as flat as if they have been sanded as well as being light and strong.  The electric blanket works well to speed things up too.  

regards,

Dave  

4

Hey Dave.

Yes you sure can, I do it on every board…

The resulting laminate is compressed so it’s flatter and the weave it pressed tighter to the blank while the peel ply removes excess epoxy resulting in a stronger/lighter laminate… You can add things like 2/3 deck patches and small foot-bed area patches and the bag’s compression ability nearly make the raised edges of the patches disappear, nearly…

You dont have to spend a fortune on the dissposables such as peel ply’s and breather fabric, as you can get all you need at the local bulk fabric store… Just look for fine / tightly woven nylon that is white… ask if they have any in the discount bin… breather is usually poly batting, but I’ve used terry pajama material with good results…

 Some guys bag with out any peel or breather fabric, but the resin applied when laminating stays in the cloth as it has no where else to go, and the bag sticks down to the rails prematurely resulting in an uneven clamping force with the possibility of trapping air under the flat areas… You do get a shiney  finish on the top this way though but you have to squeegee the bag… I don’t see the point, if you’re not going to remove excess resin…

Another great thing about vac bagging the glass on is the flattening and tightness you can get the laps to sit, and they’re bubble free if done correctly…

I shape my rails exactly how I want them to look when finished, with sharp edges towards the tail. The vac bag lets you lap these sharp edges without having to “de-tune” them prior to glassing, then have to pour an edge bead to sharpen it up again…

So you get:

 tighter, stronger, flatter, lighter,less bubbles and laps that are molded to the rails…

I just finished a board with an epoxy acid splash deck inlay that required using a lot more colored resin for the inlay, to try to avoid muddying… This left the inlay loaded with too much epoxy… I placed a piece of nylon peel ply over the deck inlay, and placed the board on the vacuum table for 1.5hrs. just to pull out all the excess resin… It did that and pulled off all the overly muddy resin that was sitting on top…

 

 

5

Hey speedneedle

Was planing on filling and sanding anyway. Was thinking more for the benifits of keeping shit out of my lams while it cures for 4 hrs, now that I'm pretty much out in the open.

Also might help with gassing and bubbling. I used to heat up my lam room, lam, then turn off the heat and let the room temp slowly drop while curing. that way the blank was sucking not blowing. Now I dont have any real temp control so if I can bag it, I should be able to keep shit out and eliminate gassing. The electric blanket thing might help with curing too.

 

"You dont have to spend a fortune on the dissposables such as peel ply's and breather fabric, as you can get all you need at the local bulk fabric store... Just look for fine / tightly woven nylon that is white... ask if they have any in the discount bin... breather is usually poly batting, but I've used terry pajama material with good results..."

 

Might have to go to spotlight and have a look.

Cheers

6

luv the vac bag, in this hot weather i can mix my epoxy 50/50 and have plenty of time to bag the board then in 4 hours remove it from the bag and start on another board to bag.

450×600 20 KB

7

Boards are looking good lakes…   How did you like the innegra?   Was it what you were looking for??

I’d love to try that baby with a kite…"))

Yeah , bagging laminates aint’ no big deal, and the pin holes are minimized if you time it right… I used to bag  60/40 fast to slow hardener, but just use fast now.It tends to set up quicker and you don’t have a chance of pulling out too much epoxy…

Speedneedle:

I’m a compsand builder like yourself, unfortunately I have to put more stuff “under the hood” as it were, things like footstrap inserts, extra foot bed glass and hardfoam, HD finbox inserts, reinforced  leash cups etc… If I can save weight, apply more glass and less resin, I have to take the opportunity… Vac bagged lams. help me do this… I don’t get many pin holes these days as I don’t go crazy and try to pull out every drop of excess of resin like I used to… I still have to hot coat though, but who doesn’t?

8

KITERIDER,

I like the innegra s in 2 oz. I have been able to get it in  30" wide , the 6/2inn bottom and 4/4/2inn top seem to work great for my wakesurf stuff, only dents on the deck were from a fatty sinking the board in a ski stance as she got caught in the prop wash behind the boat, no dings on bottom. That board works better as a twin, a little locked down with a 4 fins in . I will need to move fins up 1" if i plan to use it as a quad board again.

 

9

Hey Guys

Just spoke to the guys from ATL composites.

To buy a bag, peel ply and breather cloth will add about $150- to the cost of a build.

Will probably get 3 boards out of it.

That is all throw away items and doesn't include the hoses fittings etc.

Doesn't seem worth it.

Must be another cheeper way to bag.

Cheers

10

Hey MDS.

Like I said above; You don’t need to buy the “pro” bags, peel and breather, be creative! …Look around the hardware stores, the fabric stores,…

A lot of guys just use 6mil. poly moisture barrier plastic and fold it in half to make a 30" wide bag of any length… You stick the sides together with mastic and or “tuck” packaging tape to seal the bag’s sides and one end… then seal  the open end with mastic after inserting the board…

I paid $1.50  per yard for some nylon peel ply I got from the “ladies” fabric store… It’s amazing what you can find there that works well for board building…

I use the “pro” bagging film and make my own bags as described above, but they’re NOT thown away at all ,but are re-used over and over until demolished… This film cost $6 per yard and is 60" wide… If you bought 5 yard @  $30 total, you could make 2 bags 30" wide and 2.5 yrds. long… They would net you 20 shortboards if looked after, maybe more… Leave the breather and peel ply out all together if you want to save more $$…

Anyway you look at it it cost’s more to vac. bag, but results in a stronger board…

Coil boards utilize vac. bagging and some hi-tech laminate materials to make some of the most sought after boards on the market… It’s the price you pay for hi-tech / hi -quality… If you don’t feel the benefits of the extra cost, leave it alone, it’s not the end of the world…

11

Thank Kiterider

Will have a look around and do some testing I think.

Cheers

 

12

[quote="$1"]

I am already building a vac pump from a fridge compressor as we speak and as I will now probablly only build 1 or 2 a year for myself, I dont want to spend if I dont need to.

Another plus for me being in a bag would be to eliminate any contaminants that are flying around as now my building area is a pretty windy spot in the garage.

[/quote]

 

I think the key part is the 1 or 2 a year.  I think Speeds advice is the best at that output level.  How about making a plastic tent for the flying contaniments?  The rest of you guys doing the bag finishes are heroes in my book.

13

Kiterider,

I am definitely for bagging but I think that it is overkill for something like 1 4oz over veneer.  On a 5-10 that's only something like 100 grams of fabric.  Definetly the way to go on a KB that's going to get jumped 30 feet and has multiple layers of strategically placed fabrics.  I've done plenty of windsurfers and kiteboards where it is defintely an advantage.  Also quite a few surfboards with the so called high-tech non-woven and other specialty fabrics where bagging is the only way to go.  BTW the High Tech brand mentioned in this thread are partly bagged and partly hand laminated.  I learned to bag from Greg Loehr and in the beginning we used some crazy stuff.  Poly rope and towels for bleeder and other "stuff".  Definitely lots of materials out there cheap that work extremely well.  I still use the same vac pump that I got 20 years ago from a Surplus outfit in Nebraska for like $20 on a tip from GL. BTW what is your usual layup on a KB over what type of core?  

regards to all,

Dave

14

Hey Dave.

I bought some K.K. epoxy this spring, with the intent of using it for some quick hand lam situations…So far, I’ve only used it for hot coats as I still feel there are benefits to bagging my laminates…

I’ve also had a pump for years, so it’s not such an expensive leap as it is for MDS…

I now run 2 pumps that are cross connected with a bypass system. One large pump that pulls over 5cfm for quick clamping, then  I switch to a small medical aspirator pump after everything is tight…

My layup for a kite surfboard is ever evolving, but is basically : 3 X 3.2 oz decks  over  1/8" A 400 core-cell  on  1.5# eps core., Foot strap patches as required… I’m building durable for those who intend on jumping a lot and reducing the structure for strapless riding…

The bottom is the same, but usually only 2 layers of 3.2oz. with a finbox covering butterfly patch… My rails are 5/8" A 500 core-cell for a perimeter stringer effect as well as durability… The 1.5# EPS is completely surrounded with the core-cell to reduce water intrusion problems…

I have been using bamboo veneer in combiation with the above lay-up, but never full lenght on both sides as that would be extremely stiff…

15

Good info on the nylon fabric/ terry replacements for peel ply and breather.  Certainly an improvement on the window screen I’m using now!

How do you deal with the rails?  Do you stop the fabrics short of the rail to stop crinklys?

Much appreciated

Red

16

Sorry Red, I’ve been out kite surfing for the last 2 days after work ( 20 to 30knot days!!) , and haven’t had time to look in here at sways

I tape off the bottom or top of the board just like you would for a cut lap about 1 to 1 1/4" in from the edge of the rail, although I lay down a double layer of tape directly on top of each other… This is important, because you have to cut away the overhanging glass after it has hardened in the bag… The double stacking of the tape makes this remakably easy and quick… I posted something about this a month ago or something, on a lap cutting thread, and it goes into more detail…

Anyway. you laminate your board just as you would a non vacuum bagged board, squeegeeing the laps over onto the other side over the taped off area…

You want the glass to be as smooth as a hand layup, then you apply the nylon peelply which is cut slightly larger than the lapped glass… You squeegee this down to the laminate as smoothly as if it were just another layer of cloth all the way around the rails… You then apply the breather in the same manner, but you don’t have to be as fussy… The reason I do this is because if you cut the peel and breather short of the lapped rails the bag will stick to the rails as soon as you apply vac. pressure due to the smaller surface area of the rail…   The excess resin will stick to the bag in seconds  and  the bag will not be allowed to apply an even pressure to the flat bottom /deck areas… I hope this makes sense, it’s second nature to me, I don’t have to think about it… The other reason I wrap the peel ply and breather around to the taped off area is you wont get any imprinted lines on /in the rail glass like you would if the fabric fell short…

This is my way, not the only way,

The key is you don’t want the bag to stick to any one spot more than anywhere else, even clamping pressure is important… If you get your laps really smooth and apply the peel ply the same, you won’t have any wrinkles or creases in the lapped glass… That being said it does take practice…

 Some guys don’t use peel or breather at all but squeegee it around,   i’ve tried this and didn’t like the results… I pull the cloth tight around the rails with my thumbs as the bag sucks down to the board… I sometimes switch the pump off and on to allow you to do this and remove wrinkles and creases in the bag and other stuff… Some day I’ll makea video, it’s easier than describing it, that’s for sure!!! 

One more thing:

Don’t try to peel the dried peel ply off from the inner edges (center of board) of the laps out towards the rails, you’ll peel the lap glass off the board…You’ve got to remove the first strip carefully and get to the  flat middle of the board, once there, lift the peel ply and cut and peel off the nylon from the center of the board out towards the rails so you don’t lift the glass…I learned that the hard way from being over zealous once , and in a hurry  un-wrapping a board one morning… I had to patch about a 1" square piece of torn away rail lap…

17

Cool.  Thanks for the info.  May more good winds blow your way.  I remember the other thread.  I’ll have a look at it and then try to adapt the technique to putting tape on the rails of a veneered blank I have waiting and then to lamming the whole board.  Off to the discount fabric store…