Body work- Bondo, glaze puddy, bondo hair?

[MustangMike67fb]

Never working with a fiberglass body before, I was wondering if typical bondo, glazing puddy or even the fiberglass bondo will adhere well enough to the fiberglass. I know fiberglass tends to flex a bit and i am afraid of repairs cracking off. Thanks in advanced - Mike

 

[Rick]

Never working with a fiberglass body before, I was wondering if typical bondo, glazing puddy or even the fiberglass bondo will adhere well enough to the fiberglass. I know fiberglass tends to flex a bit and i am afraid of repairs cracking off. Thanks in advanced - Mike

Any 'glass repairs should be done with resin and cloth or matt depending on what your doing.If your joining two panels go like i said with the resin and cloth or matt then on the out side i do what the 'Vette shop here does he has a fiber fill he mixes with the resin to make a fiberglass bondo type mixture this way he gets full coverage and "bite"with the filler and not just a fill job with bondo which WILL crack.Just his and my opinion.Sone youll have 13 reasons why i'm wrong but thats ok this is what the Vette Custom shop does.

 

[Gerry]

Any 'glass repairs should be done with resin and cloth or matt depending on what your doing.If your joining two panels go like i said with the resin and cloth or matt then on the out side i do what the 'Vette shop here does he has a fiber fill he mixes with the resin to make a fiberglass bondo type mixture this way he gets full coverage and "bite"with the filler and not just a fill job with bondo which WILL crack.Just his and my opinion.Sone youll have 13 reasons why i'm wrong but thats ok this is what the Vette Custom shop does.

100% correct. Any crack in glass needs to be ground out as deep as you can go and then covered with glass and resin to a point just below the surface. Best way from there is a 'flow coat' surface on top which can be sanded and finished ready for primer. Be warned that any exposed fibers will take water on board due to the capillary action of the fibers.

The secret is to make sure when you put on a flow coat no fibres are expose... especially the neds.

FLOW COAT is available from any GRP supplier and is like gel coat but put on after the glass has been layed up rather than first as you would do if you are moulding

 

[Ted Brown]

If you are only doing minor body imperfections, whenever wanting to use Bondo types of fillers, be sure to sand first with about a 16 open coat paper to rough the surface, that will give the Bondo something to hang on to, also make sure the surface is clean from dust, wipe with enamel reducer for final cleaning... I myself have had very good luck with this technique, still no cracks or anything loose in over 20 years... Have fun with your build

 

[Mr. Fixit]

Mustang Mike,

All of this information is correct, however you need to define exactly what you are planning to accomplish. Are you repairng damage to the fiberglass structure, or simply filling in uneven areas in the surface? If it is a structural repair, the information regarding grinding the surface down and using resin (polyester not epoxy) with cloth or mat is accurate. If you are simply surfacing blemishes or low areas prior to blocking, do what Ted suggested with the 16 grit paper and then you can use a good quality polyester filler prior to blocking. I hope this helps.

 

[Gerry]

Mustang Mike,

All of this information is correct, however you need to define exactly what you are planning to accomplish. Are you repairng damage to the fiberglass structure, or simply filling in uneven areas in the surface? If it is a structural repair, the information regarding grinding the surface down and using resin (polyester not epoxy) with cloth or mat is accurate. If you are simply surfacing blemishes or low areas prior to blocking, do what Ted suggested with the 16 grit paper and then you can use a good quality polyester filler prior to blocking. I hope this helps.

Heres to that
Gerry