Filler Materials

The type and quality of the fillers used on your vehicle is a critical factor in the way the finished product looks and lasts.  Below are products that I've found to be some of the best on the market for the price paid .  These products are easy to work with as well as long lasting when applied correctly. 

The LONG STRAND fiberglass filler is stronger but doesn't spread as smoothly and is better for repairs to broken or missing pieces of fiberglass. 

SHORT STRAND is better used for repairs on metal surfaces or on broken fiberglass parts where there are no holes to span. 

MILLED fiberglass filler is best used where the panel strength is already good and the panel just needs the seams filled.  Milled filler is good when used over welded seams that need a moisture resistant filler.

Dynatron Fiberglass Fillers

Fiberglass fillers get harder than bondo-type fillers and tend to be more
moisture resistant.  These fillers are usually good for filling over seams in
metal or repairing fiberglass parts.

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(long strand filler)
#472    Quart
# 474   Gallon
(short strand filler)
# 462   Quart
# 464   Gallon
(milled glass filler)
# 642   Quart
# 644   Gallon


Dynatron Products

I've found that these fiberglass products work well for a number of different purposes.

I use Dyna-Hair (long strand) for areas where I need strength over a larger open hole or to stabilize an area.

I use Dyna-Glass (short strand) on areas that have been covered with foil tape or where a hole is small.

I use Ultra-Glass (milled glass) on top of welded seams to create a barrier against potential moisture problems.

The longer the strands in the paste the more difficult to make the surface smooth during application.  When you apply the milled glass it can be smoothed and pushed into the surface imperfections.  Long strand will have air pockets and need further filling to get a smooth surface but the longer strand is stronger over unstable material.

Rust or Hole Repair With Fiberglass Fillers

Auto body store
After cutting the rust out back to new metal grind the surrounding metal clean then countersink the edge of the hole and apply a "good" aluminum tape then cut the tape so that it lies within the sunken area.   Using a rounded tool (like the end of a screwdriver handle)  press the tape edge so that it gains maximum adhesion to the metal then lightly scuff the aluminum tape with 80 grit being careful not to tear the tape.  Apply the fiberglass filler making sure to press it into the surface so that it will adhere properly then sand and apply body filler to fill the indentation.

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Body Filler

Body filler is used to level he surface after the metal work has reduced the damage to slightly uneven metal.  After straightening the metal is usually ground with a grinder in order to clean the metal and give it some "tooth" so that the filler can bond well with the surface.

After the application of the first coat of filler the spreader is cleaned and the filler is allowed to get about as hard as cheese at which time it's easily leveled or shaped with a "cheese grater" blade then allowed to fully harden then it's block or board sanded to finish the leveling process.

Link to Filler Pricing

Some Recommended Fillers

There are MANY different fillers on the market and many of them work well.Here are a few that we have found to do an excellent job for the price.

Auto body store


Polyester Glazing Putty

These new putties (below) took the place of the older ( lacquer type ) putty for finishing the filler work before priming.  These putties sand easily and do not continue to shrink after the paintwork is done.


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Evercoat Polyester Putty
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Polyester Glazing Putty- Very fast hardening, good in cooler shop temperatures and for small spots during warmer weather.  Should not be used for application over areas larger than about one square foot during warm weather. #400 Quart
#407 1/2 Gal.
Euro-Soft Putty- Slower hardening, good for larger areas, excellent over galvanized and OEM anti corrosion treatments. #408 Quart
#409 1/2 Gal.
Spot Lite Putty- Medium speed hardening excellent over galvanized and OEM anti corrosion treatments, good all round usage. #445 Quart
#447 1/2 Gal.

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Repairing minor dents like this BMW with hail 
damage is quick and easy with Polyester Putty.

Evercoat Easy Sand Polyester Filler

Creamy Liquid Filler
in a Pump Container

Auto body store

Easy Sand
is q
uickly becoming one of my favorite finishing fillers  because of it's more liquid nature this filler spreads quite smoothly without fear of pin holes.  I really like the way you can add it to the other fillers to get the consistency you want.

Evercoat  Flexible Polyester Filler

Auto body Store

Poly-Flex has about the same consistency as
Easy Sand but after it hardens it remains flexible.

This is a great product for filling gouges or low spotsin semi-rigid surfaces but is not a replacement for plastic repair materials when the plastic surface is broken.

Disclaimer: The ideas and methods described in this web site were developed under unique situations. Since these situations cannot be duplicated, you may get different results. Use and application of any of the site's content is at the user's own risk.

All information on this site is the property of Stuart's and may not be reproduced without prior written permission.