Magnum Venus Plastech Impregnator Roll - Manual (Page 15)

CHAPTER 5
RESIN/GLASS RATIO SETTINGS
The resin content is controlled by micrometer adjustment dials on the vertical roll plate supports.
By opening or closing the adjustment dials, resin content can be varied to +/- 2%
Through experience, it has been found that a 40-48% glass content works best for optimum
performance of the Impregnator. Less than 40% glass, the laminate is very resin rich and
dripping below Impregnator is a problem. More than 48% and the glass content is so high it
does not wet-out well and additional effort is required for secondary hand rolling, etc.
Due to various conditions; temperatures, viscosity, reinforcements employed, etc., it is
impractical to give an exact setting to control resin content. Therefore, an approximation must
be made and material burn out tests performed to get an exact resin roll setting. To obtain a
very close approximation the operator should first measure the total reinforcement thickness
(measured dry) and add to this dimension .025 to .035 to obtain proper roll setting.
Example: Woven roving thickness = .030
Chopped mat thickness = .025
Added clearance = .030
Total = .085
A .085 gap setting of the rolls would be the starting point to determine glass/ resin ratio. A burn out
test will be required to get extra data on glass content.
NOTE: Different materials- reinforcements and resin may look very different when wet-out by
the Impregnator compared to what you are used to seeing. For example: a woven roving all
appear to be much higher in resin content than it actually is. On the other hand, a heavy mat,
(1-1/2
– 2 oz), will appear much dryer than it is. A combination mat and roving will appear dry
on the mat side and wet on the roving side. Through experience, an operator will be able to tell
when he is close to the proper setting on the rolls when he first starts and can adjust
accordingly. By keeping a record of the burn-out tests of your various laminates the operator
can change roll settings by checking records.
NOTE: Burn-out tests should be conducted when a precise glass to resin ratio must be
maintained. Burn-out tests will give exact data for setting nip of resin rolls. To perform a burn-
out test:
1. Cut a sample of cured laminate and weigh it accurately.
2. Burn all resin from the laminate by use of a torch, oven or other suitable method.
3. Weigh the glass that is left after burning away the resin, again being very accurate.
4. By comparing the before and after weight you can obtain a very close glass to resin ratio.
The following steps should be taken when the machine is first set-up, and when there is any doubt
as to the accuracy of the roll settings.
1. Close rolls completely by turning the micrometer knobs counter clockwise until they are
completely free, just spinning on the shaft with no load on the knob.
2. Looking up from below the resin rolls, check to see if rolls are completely together; no gap or
light appears between rolls at any point.
3. With a feeler gauge set for .030 turn both micrometer dial knobs clockwise until the gap,
measured with the feeler gauge, is .030 across the full width of rolls.