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Getting started /Fiberglass repair kit and materials for a typical fiberglass repair.



"Apart from having good preparation for our fiberglass surface, it is equally important to use the right materials for the job."



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Today, fiberglass repair kits make it a very convenient way to do those much needed repairs around our home, boat or car and so many other things in between.

With a growing number of fiberglass products coming onto the market it is becoming a matter of choice as many products have a universal application, although it is still important to know which ones will do the job and do it successfully.

There are many brands and types of resins available today just as there are different types of reinforcements for different applications, so how do we know what to use? Well for most, they just go out and buy a Fiberglass Repair Kit and for most of these people that will do the job.

So, what else do we need? For a start, we need to know what we are repairing, the most common forms of fiberglass repair will come from boats, personal watercraft, cars/4WD and trucks.

Typical fiberglass car spoiler damage The other thing to consider is "is it worth
repairing?", this is a very sound question we need to ask ourselves as some items (like flares from 4WD to front fiberglass spoilers on sports cars) could be an expensive and time consuming affair ending in "it would have been far cheaper and quicker to buy a new or second hand one and get it resprayed (to colour) if needed.

With this as a guide, cracks/fractures or small holes should be easily fixed using one of these fiberglass kits.
Fiberglass repair kits can vary in "what is in the box" as we will see here,
Fiberglass repair kit but basically we will have our resin, catalyst, mat (which is csm-chopped stand mat), mixing and/or measuring cup, mixing stick, gloves and instructions.

So, what about brands? is one brand better than the other? generally speaking the difference would be the price and any extras you might get apart from the basics.
3M fiberglass repair kit
Fiberglass materials in general have to meet a countries standard of quality and assurance, so it will be a personal choice of what kit you would buy. Always follow the directions supplied with the kit and make sure you wear appropriate PPE when doing your fiberglass repair.

Some times when we have failures we usually blame the product and sometimes (rarely) it can happen, depending how long its been on the shelf and the conditions it has been stored at.

But all in all the problem usually is us, so we need to follow instructions and not make up our own to suit the situation at the time.
The resins used in a fiberglass repair kit would be a general purpose waxed polyester resin (orthophthalic resin).

When our repairs get larger and require bigger quantities of fiberglass materials or if we require a different grade, epoxies or we need different types of mat and not just a fiberglass kit, then we need to be looking at fiberglass suppliers who specialize in these to suit our needs.

Some of these businesses and companies can be found here under Links-Fiberglass suppliers or in your local yellow pages in your telephone directory under Fiberglass Materials depending on your country.

In our next section under Getting started/Fiberglass canoe repair we will cover from start to finish the whole procedure in detail of repairing a crack in a Canadian style fiberglass canoe.

By the way this repair can be adopted to many different fiberglass repairs including cracked panel work on fiberglass cars, small boats, spoilers and body kits as examples.

So here is a list of the products that we will be using to cover this repair, depending on your fiberglass repair you can take out or add to it as you wish depending on what you may already have or the repair it self.

For more detailed information on all materials associated with fiberglass repair and/or in construction this will activate when done.
fiberglass materials and associated products information page.

With this canoe repair that we will be doing, I will use a polyester fiberglass repair kit to fix the damage on the hull as this is what most people would buy to repair it, although I would use a isophthalic resin in the trade most people may not be able to get this grade of resin easily to do a repair, so I will put myself where most people are.

The main difference between the two resins is that "Iso" grade is a stronger and is more chemically resistance than "Ortho" grade which is found in fiberglass repair kits which are used for general repair work.

I have heard some suggesting to use epoxy resin to do the repair, if the canoe was made of epoxy, then I would use epoxy for the repair.
Fiberglass chopped strand mat and woven rovings
So lets have a look at what we need in the way of tools, if you haven't been here before you can go here for a list of tools that we will need for this fiberglass canoe repair, we will also have a list of tools and materials together at the end of this page.

Now, some other things we will need will be some colourant so when we finish our repair we need to make it look and /or blend in with the rest of the fiberglass canoe or object that we are repairing.

With our finished coating we have a choice of what we can put on it, if our canoe, boat or article is new or not very old (say less than 2-3 years old and been garaged or undercover) and has a glossy gelcoat finish then we will get a pretty good match in the original gelcoat colour range.

Gelcoat comes in a creamy liquid as a natural base (non-colour) or white as the standard colour and can be tinted to any colour with base colours as a starting point (colour card), remember though that gelcoat will stay tacky when it sets unless you add a little bit of wax and styrene to it or spray some PVA release agent over it, so in this case we could use a gelcoat repair putty which is gelcoat with fillers and wax added and made into a rich, thick and creamy paste.

For cracks, scratches (that cannot be cutout with polish) gouges, screw holes example can be easily filled with a gelcoat repair putty, this putty is white in colour and thick and comes in economical 375 gram tins with catalyst supplied and dries to a non tacky finish.
Gelcoat-repair-putty
On the other hand if our fiberglass canoe or object is older and show signs of gelcoat or surface breakdown of the finish then we can paint it in a 2 pac or a single pack finish depending on our budgets and what we have on hand or whats available to you.

Some objects like repairing a fiberglass wheel arch flare on a 4WD or sports car will be better off spray painting the whole unit, more so if the colour is a metallic or pearl colour as this will blend in and will also save time cutting in and polishing it to match the surrounding area.

So if we are not going to be using a gelcoat as our final colour then we will need the following materials to finish our fiberglass repair.

A small tin of car body filler that is suitable for fiberglass and that will go under 2K paint (2 pac), a cork or rubber sanding block, some sandpaper of 80grit, 150grit and 320 grit, a spatula, paint scrapper or a plastic disposable bog spreader and a clean plastic lid from a 2 litre ice cream bucket or something flat and clean to mix some filler up on and some clean cotton rag.
Acetone-Prepsol-Kahfil auto filler
Along with this we also will need some primer, all this can be obtained from a hardware shop and/or a auto paint place.
 Primer-filler
Septone is one of many top brands that work well and come in handy spray tins and is easy to use and sand, always follow the directions on the can before using.

Now, we will need a mixing container of sorts to mix up the resin in unless one came with your kit, so a clean tin that will hold enough resin to do the job will be fine (mixing containers).

Make sure it is clean and dry before use, a flat stick like a wooden ruler (fiberglass repair kits usually come with paddle pop sticks) or something similar to stir the catalyst through the resin when you mix it in.

Next we will also need some sandpaper to level the gelcoat or car filler, for gelcoat a sheet of of 80grit, 150gt, 240gt and 320gt in dry paper and a sheet of 600gt, 1200gt and 2000gt in wet n dry, plus a rubbing block.

The reason for so many different grades is that gelcoat is a hard coating and requires many grades to bring it up to a very smooth surface for easy polishing with a cut and polish.

For car filler we will need one sheet of 80grit, for the primer one sheet of 320gt STOP? hang on!! why do we need so many sheets of sandpaper for gelcoat compared to the paint system? Well gelcoat remember is made to go into a polished mold hence why fiberglass production items come out so shinny.

So now we are using gelcoat in a different situation, so we would either spray, pour, brush, roller coat or spread the gelcoat over the outer surface of the fiberglass repair and depending on how good we are it could be quite rough or very smooth or anywhere in between but either way it will require many grades of sandpaper to achieve the glossy finish.

Gelcoat is a very hard product and thats why it can shine up to a very luxurious finish, but it takes effort to do so unless we put it in a mold or lay it onto something that is shiny and prepared for gelcoat e.g. a mold. Now back to our paint system, if we are going to use a 2pac gloss paint we will need our 80grit for our filler, 150gt and one 320grt for 2pac or and a 600grt wet n dry for lacquer for the primer.

Some guys use acrylic lacquer, and others a 2pac paint and that will also depend on what we are repairing, depending on your budget one could use a enamel if you wasn't too concerned on its durability.

In our case we will be using a 2pac in a spray can and you read correctly, these days and for quite some time auto paint shops that deal in 2 pack paint for the auto trade can make you up a spray can tinted from your colour chip pre mixed with hardener and thinners, in the old days one would have to use this up well before the day was up as it would start to thicken and set and become unsprayable.

But now and for some time the spray can has a little button on its bottom so when we get it mixed at the shop we have at least a week or two to activate this button to release the hardener into the paint, afew minutes of shaking the can and we are ready to spray.

Spray max fillclean system So it is also a good idea to look at other areas around the car,  boat, canoe or the object that we will be spraying cause it is on the cards that there will be some left over, so if there are any other areas you find it would be beneficial to prepare those areas as well so they can be touched up.

Some masking tape and paper may come in handy if your spray area is near another colour, near the opposite door or guard of the car or gunnel of the boat, I think you get my idea here we do not want to get overspray on our undamaged shinny surfaces unless you are spraying the whole object.

So, lets recap on the on the basic material and tool list here, of course you can take out what you don't need or what you may have already at your disposal and also your method of finishing.



Tools and Materials
for a typical fiberglass repair.

  • Suitable PPE to protect ourselves from dust/fumes or resin.
  • A suitable grinder with a backing pad and sanding disc/s.
  • A number of sheets of sandpaper to prepare for our topcoat.
  • Sanding block.
  • A laminating roller.
  • A spatula or something suitable to apply filler or Gelcoat paste.
  • Mixing container for resin.
  • A plastic mixing board for filler or gelcoat.
  • A fiberglass repair kit or fiberglass materials to do the job.
  • A tin of Gelcoat repair putty. (if using this system)
  • A spray can of primer filler or undercoat suitable under 2pak paint.
  • A spray tin of 2pac or your desired paint system.
  • A tin of polyester based auto car filler. (if using a paint system)
  • Some acetone.
  • Some wax and grease remover/Prepsol.
  • A roll of masking tape.
  • Some newspaper to protect the surrounding surfaces from overspray.
  • A clean dry cotton rag for applying Prepsol.

Our repair will come next.