Fiberglass Delamination problems & solutions

A. Hi, cousin Lee. I am a little unclear. This is not a lined tank? Rather it is a fiberglass tank and there are some ABS components like a mounting bracket or such that you want to attach to the tank by laying it onto the wet resin but you're not getting adhesion?

Although I'm not fully understanding your question, ABS is a multi-component plastic which is eminently etchable for outstanding adhesion. The "chrome" grills on millions of cars & trucks are copper-nickel-chrome electroplated ABS and the metal sticks despite blazing sun, frigid cold, gravel strikes, and carwash brushes because the ABS was etched to a sponge-like surface ... it ought to work for you. Please get back to us with more detail.

A. Hi KW

As Ted pointed out, your spec was a little unclear.

Whereas 'we' did a lot of dual laminate work, it was normally bonding fibreglass to a thermoplastic.

There are, as you must know, proprietary chemicals for bonding, say, FRP to PVC ... but perhaps the following method, although now antiquated, might help you.

You get some ABS cement ... add ABS to it to a consistency of, say, 20% solids. Then you get some fibreglass heavy woven roving. You are now ready to coat that ABS part with the heavy cement and IMMEDIATELY press on the woven roving. Let it air dry ... and if you do it correctly, then one link of the WR will be embedded in the cement, the other one exposed ... which now allows for a perfect FRP bond.

This is how the world's first successful dual laminates were made ... 1963-ish by Alcore Fabricating in Richmond Hill, Ontario ... using PVC albeit with the appropriate solvent, THF.

If this helps you, please let us know. Thanks.

A. Hi John,

I don't quite fathom your question but will try to !

When you have a PVC sheet and want to bond fiberglass to it, there are now commercially available materials to achieve this. These you'd probably get from the resin supplier. But any good dual laminate fabricator could give you advice.

In the DARK AGES we used to make up a heavy PVC cement using THF and drop on some heavy glass woven roving ... and when the PVC 'dried', ah, we have a good lock to the exposed section of the roving... a world's first back in 1962-ish.

Whatever you do, don't expose the FRP to the ClO₃ and try, of course, to weld any new sections to the adjoining PVC.
... just had another glance at your request ... there's no product I know of that will successfully bond PVC to an existing and CURED FRP build-up .... with the above mentioned approach, the 'bonding agent' to the PVC only allows a bond to the 'new' and uncured FRP ... the only other thing I could think of is to use epoxy BUT again you'd have to use that initial bonding agent.

A. Hi Michelle,

Who in der Hell said that FRP would be good for HF acid?

Surely there are some good HDPE suppliers using moulded tanks in your neighborhood, try them !

Further, FRP tends to wick ... osmotic attack .... hence structurally the m.s. side would be attacked.

For an el quicko build up, use epoxy. But first of all, grind down the attacked areas.

A. I agree that FRP is not suitable for acid solutions containing HF, but, with a PVDF surfacing veil inside the fiberglass, bonded to it with epoxy and covered with a gel coat of epoxy, it may work for many years.

A. Hi Yi. Concrete tanks of that general size are often used for architectural anodizing projects, quite similar to your degreaser, acid, and flux tanks; and they can be equipped with various corrosion resistant lining materials.

A sometimes-used technique for leak detection, although imperfect, is an angle shaped strip of heavy gauge aluminum foil running around the tank where the four sides hit the bottom before the tank lining is applied/installed. Then some sort of conductivity meter is put into a circuit with a probe in the solution being one leg, and wiring attached to this strip being the other leg. It's not perfect because it doesn't work until the strip is wetted by the leak, but it does work.

However, I am flabbergasted by your reference to "molten zinc"! I can't even imagine a concrete hot-dip galvanizing tank :-) Luck & Regards,


Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hello Francois. As a personal opinion from a consumer who has faced the same problem a couple of times, not a professional opinion, I think you should replace it unless it is very special to you for some reason (special dimensions, aesthetic appeal, sentimental value). Water has soaked into it and caused swelling, plus the gel coat has been destroyed. It is perhaps possible to sand away the gel coat, dry it out, finish sand it, and apply a new gel coat (perhaps with materials from a boating store; boats are repaired this way) ... but it's a huge amount of work for something that can be replaced very inexpensively, and you'll never get it quite perfect. Best of luck.

Regards,