Thick biaxial glass pros/cons?

[furious cub]

Hi ive picked up 50m of 300/1200g biaxial cloth for a steal. 45$
Just wondering if this will be safe to use on a boat with polyester resin?
Whats the pros vs cons of 1-2 thick layers vs 3-5 thin layers?

Thanks guys.

 

[tunnels]

simple answers !!

Hi ive picked up 50m of 300/1200g biaxial cloth for a steal. 45$
Just wondering if this will be safe to use on a boat with polyester resin?
Whats the pros vs cons of 1-2 thick layers vs 3-5 thin layers?

Thanks guys.

what is it going to be used for ?
what's it going over the top of ??
why polyester resin ??

 

[furious cub]

A rebuild of transom/stringers/and a layer through the whole hull.
Its got a layer of 300g chop stiched to it. Its going over cured polyester
Why polyester because i dont have the $$ for epoxy. Im on a very limited budget.

 

[michael pierzga]

Heavy Biax is hard to wet out and hard to make conform to inside outside radius.

Im sure it will work... expect a challenge.

 

[RTM]

Did a similar job in a small 14' antique glass runabout, although the biaxial might not have been as heavy as yours. I used PVC pipe ripped through the middle for the stringers. First I covered the bare bottom with the biaxial cloth, then patch glassed the stringers on and then covered the bottom and the stringers with a second layer. Being that the stringers are half round tubes, made the job simple. I cut the biaxial cloth into manageable pieces and dry fit them into the boat. Then I numbered them with a magic marker and stacked them up in order. It was easy to wet out each piece, and just continued till I was done. The weather was cool, about 65-70 degrees at the time, and had no problems. I run that boat at the Antique Outboard Motor meets monthly for the last 2 years at 50 mph and have had no problems with delamination. it is very strong.

rich

 

[raf pali]

I used a thick quad axial sometime back and found it difficult to saturate with resin rolled on by hand. I had to spread resin in one side and turn it over to do the other, plus it wouldn't follow the curves. Vacuum bagging might be the way but needs equipment and the know how.

 

[michael pierzga]

If you must use heavy cloth, increase the size of your fillet and corner radius.

25mm is a typical radius for med. weight cloth. 35mm radius will be easier with heavy cloth.

Remember that fillet material is expensive. It may be cheaper to purchase the correct weight cloth

 

[tunnels]

what are you trying to do exactly ??

I have been watching this post for a few days and am at a loss and not really sure what you are really trying to achieve !! so you already have a existing boat now and you want to lay more glass over the top of what's already there !!
simple question WHY

is the boat weak in the bottom ??
is it thin ??
does it move a lot up and down ??
If it moves then how much does it move ??

Do you realise that movement and flexibility in some glass panels and glass structures is actually a good sign and that it is stronger and will take more abuse and punishment than the same panel that has little to no movement at all ??

Remember this from olden times !! a tree that bends in the wind looses no branch's !!
but one that is ridged and does not bend or move with the wind usually breaks and dies !!
Glass is very similar !!

To lay new glass over a old surface the old glass will need to be sanded or ground 100% to be sure of getting a good secondary bond onto the old surface !! any unground areas are the most likely places for delamination to start and eventually spread !!

Sounds like there are structures you are wanting to go over the top of !!
CAN YOU POST A PICTURE OR TWO SO WE CAN SEE WHAT THE PROBLEM IS ?
It maybe better and easier to cut the glass into strips of useable widths and use the joining overlaps to get even more strength in the layer of glass than trying to lay a great long wide strip all in one go . personally I would not even attempt such a thing . there are limitations that even a really a good professional glass person can do and by the sound of what you want to do is not one that I would choose even with 3 or 4 people helping !!

 

[tunnels]

I used a thick quad axial sometime back and found it difficult to saturate with resin rolled on by hand. I had to spread resin in one side and turn it over to do the other, plus it wouldn't follow the curves. Vacuum bagging might be the way but needs equipment and the know how.

silly boy for even trying to use quad in a place were there's shape !! its not the glass that's the problem its the stitching holding the glass bundles !! better in places where there's shape to use two different glasses that give you the same structure as your quad , double bias and a bia-axel !! each one half the quad weight

Good that you wet out the back side and then the top !! quad is not easy to handle and work with that's for sure !! the flatter and straighter the layers of glass the stronger it will ultimately be !!

 

[richofoz]

Short answer.
Yes standard gp laminating resin will work with that material.
But! That glass will be hard to use in many situations!


Wet out will be difficult and unless you approach it carefully you will end up with a resin rich laminate just to get the glass properly wet out.

If possible saturate the material (from both sides) on a table then pick it up and place it on the job.
Easy with small pieces but it's a 2 or even 3 man job with larger pieces...

Pros - if done properly will be lighter, stronger and cheaper ( in a perfect world)
Cons - harder to wet out and apply than several thiner layers and a higher chance of a resin rich (brittle) laminate. (excess resin can sometimes be rolled out of a part but it's labour/cost intensive and at the end of the day, a waste of resin!)

Another thing to consider the strength of the parts you are bonding to.
GP resin shrinks a fair bit and if your new laminate is thicker than the old it will distort the original glass and cause a new range of problems!

 

[furious cub]

Ok guys sorry for the late reply. I was going to use it coz it was alot cheaper then what im using atm 400g.
I believed i would also save on resin and time. But its ok i let it go. It was going to be used for a stringer transom restore the stringers are out and glass grinded back but i wanted to put one layer over the entire hull bcause i can see the color from the gel in spots.

 

[tunnels]

Its takes lots of needling but eventually we sort of get answers as to why !!
Good idea take the old stringers out and then grind everything to geta really good bond (use 16 grit discs ) really course and rough surface so the glass gets a really good mechanical bond to the old glass !
Next question what are your ideas for new stringers ?? how high and what thickness you looking at ??
you could just make foam stringers but if its an idea then will have to be done differently to what was there before but will be better !!

 

[furious cub]

What was there before was 6 2 x 6 inch thick solid timber stringers (way to much)
I would like to change these to ply wood about 1.5 x 4 inch with knees and 2 bulkheads.

 

[furious cub]

Sorry for the late replies guys. But ive decided to just stick to the 400g biax and chop ive been using. Will save me the hassle of the corners.

 

[tunnels]

Sorry for the late replies guys. But ive decided to just stick to the 400g biax and chop ive been using. Will save me the hassle of the corners.

change these to ply wood about 1.5 x 4 inch with knees and 2 bulkheads.Will save me the hassle of the corners !!
that's a big change and loss of strength so you reckon the 1.1/2" x 4 " is going to be ok ?? and you going to use Biaxle glass so you don't have to worry about the corners !! and its 400 gram !! so how many layers you anticipate using :?:??with csm as well?? or you going to leave that out ?? You going to do the stringers first and the knees and bulkheads after ?? or all at the same time ??