Cloth on Cloth

In building a boat in a mold, can you laminate cloth on cloth or do you need to apply a layer of mat between them. I examined an Allison and found no signs of anything but cloth under the deck.
Thanks, Tim

 

Depends exactly what the reinforcement is, unidirectional can be laid up without chop in between, but generally if it is woven material, no, I think it might delaminate too easily..

 

What type of resin are you planning to use? With epoxy you don't need mat between the layers. With polyester you need to use mat between each layer of woven or stitched fabric, but use some other type of fabric instead of cloth. Cloth is very expensive compared to other woven or stitched fabrics and since you need to use mat between each layer, you end up with a great deal of glass and resin that isn't adding much strength, this results in a heavy weak laminate.

 

Don't think he is using epoxy to laminate a hull, I assumed poly or vinyl ester, when you say stitched, are you including unidirectional rovings ?

 

It really depends on what he calls cloth, some people use the term cloth when referring to all types of glass other than mat (actually some include mat too).

Any stitched or woven product should have a layer of mat between them, without it there is more of a chance of interlaminte shear, at least in hand lamination.

 

You're scaring me ondarvr. Your glass supplier, forgot the name, told us you don't need mat between layers when infusing.

-jim lee

 

Mine told me it wasn't needed when doing a wet on wet hand lay-up, or multiple layers at one time. I never tried it though.

 

I would be using vinyl ester and the cloth looks like standard mat you would get from Home Depot or just local suppliers. I am wanting to get into infusion, will it work with that laminating process?

 

Correction, standard cloth.

 

In order to solve these terminology issues, what does the package of fabric say Titan? I mention this because

Mat doesn't look like cloth. Again what does the package call it's contents, or better yet a photo of the material you're calling regular cloth that looks like mat.

 

With VE resin you do not require csm between stitched or woven cloth for open lamination.
Once you start increasing the fiber fraction by vacuum consolidation the requirement for stronger resin goes up. But as most of us will still be using the same resins using a combination cloth, stitched UD with a thin csm layer (more resin rich inter layer) is a good idea.

Even with epoxy resin you can see the increased need for stronger resin with infused laminates as compared to open laminates. This is evident when you cut these laminates with a jig saw, the infused laminate will fracture more than the open laminate.

As infusion is becoming more common and I notice some still use polyester resin for this I wonder if it is a step in the right direction?

 

Thanks all for your in put. Tim

 

In hand lamination you should to use mat between each layer, even with VE, but its not uncommon in some market segments to use multiple woven or stitched products back to back. Its not the best method, but it works for them.

In hand lamination the loft of the glass will create a resin rich layer between each woven or stitched fabric, this resin rich layer is weak and can fracture when stressed. Mat fills in this resin rich layer with at least some glass which can make a big difference in how well the laminate holds up to stress.

With infusion the glass is compacted and this helps to eliminate the resin rich layer between each fabric, which increases the strength and lessons the need for mat.

 

It depends on the resin you are using and the time interval between each layer.

You can laminate cloth on cloth if the time between layers is such that the preceeding lamination is still tacky and has not cured otherwise a layer of chopped strand mat is to be used in between layers.

This applies only to Poly and VE but not for Epoxy resin. Epoxy has better resin to resin adhesion so a tie coat is not necessary.

If you are infusing, cloth to cloth, biax to biax, uni to uni is acceptable since you are practically laminating in one go.

 

Naw, we're infusing biax to biax using VE. ondarvr's been to our shop a couple times and knows all about our process.

-jim lee