Tuesday, November 18, 2008

There was a mishap and this chunk of the front plastic bumper was torn completely off.
A local body shop owner advised that it could be repaired by gluing it back together with
3m 08115 Panel Bonding Adhesive and SEM 70006 tape.

Here are the supplies and tools used, remember this is a soft porous material. It requires coarse
cutting tools at fast speeds. Avoid heating the material and closing its pores, they are critical
for bonding adhesion.
Supplies were procurred locally, or can be bought online. There are no endorsements and
all products should be used in accordance with manufactures MSDS and TDS.
All common safety precautions should be used in addition to tool manufactures instructions.

After cleaning the bumper cover and piece with soap and water,(Dawn or Wisk laundry),
It was determined to be best to repair the cracks in the piece first.

Most instructions will advise to apply the reinforcement tape and glue to the back side first.
This didn't work well because it is difficult to work the tape and glue in place and keep the outside surfaces aligned.
Next the cracks were beveled out and the torn edges prepped.
A little material must be removed from the torn edge for proper fit,
the plastic is stretched and the edge is jagged and will not allow proper fit and alignment unless it is cleaned up.

Not all edges will properly align at once, remember that it was ripped off with a road sign and never will be perfect again.
However, if time is taken, and only the areas that line up well are "bonded" and cured before moving on,
the results will be surprisingly satisfactory.
Ready for 8115 Panel Bond, it is not necessary to have a dispensing gun. It is only necessary
to push out what you need in a cup and mix it by hand. It will take several days just to bond the outside.
Applying heat was tried but the plastic expanded too much and moved around when heat was applied
from a heat gun.

Close up of prepared splice.

First glue, filled the beveled cracks on the piece that has the reinforced tape on the back,
(big red circle).
The small circled areas lined up nicely, the rest of that edge can be done after the glue
cures. It all could not be held in place all at one time.

Looks pretty good for a piece of torn up junk, now to do more prep and glue up more
of the torn edges.

It took 3 different glue mixes but the refection show that it is aligned as good as can be.
This is a 23 year old piece of plastic.

A groove was ground for a piece of stainless welding rod, the small perpendicular grooves
are ground at an angle to help the bonding material hold.

Time to fill the hole, this piece was not recovered, a piece from a doner bumper will be used.
The doner bumper isn't great, but the piece needed is fine.

Start big, take your time.

Donar piece is fit and back side prepped.

Doner piece tapped in place, only a couple of areas align well enough
to bond at this time.

The areas align well.

A couple of grooves were ground and some strands of polypropylene twine (baler twine)
are embedded in the 8115 for reinforcement.

Waiting to cure so the remainder can be aligned and bonded.

No comments: