When applied to a surface, Microseal® fills fine pores, micro-cracks and joints between fitting parts. It becomes a hard, insoluble, durable, non-toxic, and invisible solid which creates a pressure-tight seal that is impervious to boiling water, sea water, steam, alkalies, acids, alcohols, greases, oil, kerosene, and many other chemicals.

Are you sealing a leaking boat tank?

This is a popular use for our Microseal® products! Check out THIS ARTICLE from PassageMaker magazine’s 2000 issue for application tips and tricks.



metalblockNo impregnating equipment, pressure, or high temperature is required when using Microseal. The sealant can be brushed on or sprayed on, or the articles can be dipped. Hardening occurs at room temperature. Baking is not necessary.

When brushing or spraying it is preferable to apply on both sides. For spraying any conventional sprayer such as for paint, insecticides, etc. can be used.

For dipping, the required period of immersion ranges from a few seconds to fifteen minutes depending on the surface conditions. The longer time is recommended if the pores are very fine or contaminated by water, grease, lubricant or dirt. Also, turn your pieces over to prevent airlocks. If troubled by dripmarks, one can prevent those by pulling castings slowly from the sealant.

Microseal can also be forced into the pores with air pressure. This is not really needed though.

Microseal-DS (AC or MEK)

Is a double strength Microseal which gives it more bonding power and allows for more build-up than regular Microseal. Sealing can be done by dipping or by brushing on. Spraying might clog your apparatus.

The application of Microseal-DS is the same procedure as for single strength Microseal.


Microseal and Microseal-DS (AC or MEK) are dry to the touch in about one minute. Hardening starts immediately and is completed in three days. Ideally three days should be allowed before pressure tests. However, one day is often enough time for tests. To speed up hardening, air dry for one hour, then heat at 150 degrees F for about one hour or blow with cold or hot air using fans.

The film is normally clear, but may turn opaque because of high humidity or drying too quickly. This can be prevented by drying in a closed container which slows the drying process and lowers humidity.

Also, an opaque film can be made clear by wetting the surface lightly with methyl isobutyl ketone (MIBK). MIBK dries slower than MEK.

Miniseal is dry in about 5 minutes, usually with a clear film. Hardening starts immediately and is completed in three days. Ideally three days should be allowed before pressure tests. However, usually one day is enough time before tests. To speed up the hardening, have the articles air-dry for at least one day then gradually heat to 180-200 degrees F for two hours. This treatment will also improve Miniseal’s resistance to water. Resistance to water can be improved further by the following: air dry for at least one day then gradually heat to 180-200 degrees F for two hours. Then gradually heat to 300-400 degrees F for an hour.


For colored Microseal, add organic dyes (preferably non-alkaline) that are soluble in ketones. Dyes are available in all colors but not in white. For white, you may have to use a pigment, such as antimony oxide.


Castings MUST be dry and clean! Any conventional cleaning method can be used, but you should be sure the cleaning solvent or water has completely evaporated before Microseal is applied. Water may spoil liquid Microseal® by causing precipitation of the resins.


  1. Make sure your castings are dry and clean.
  2. Use regular Microseal rather than Microseal-DS when treating fine porosity.
  3. Warm castings to about 150 degrees F before immersion into the sealant. A warm casting will suck in the sealant better than a cold one. This low heating has the additional advantage of driving any possible water remnants from the pores. Water contamination can spoil the sealant.
  4. Have the sealant preferably at room temperature. (+/- 68 degrees F)
  5. Immerse your casting for 10-15 minutes to give the sealant time to penetrate.
  6. Turn your casting at half time to eliminate any possible airlocks.
  7. Though one day is usually enough for the sealant to harden, it is preferable to give it three days.
  8. In case of coarse porosity it may be necessary to reseal by quick-dip to get some build-up of the seal without permitting the original seal to be dissolved again. In this case, it may be easier to use Microseal-DS.
  9. If pressure is used to force the sealant in, take care to taper off at the end of the procedure. Otherwise the sealant might be blown through and out.


Give as much time as feasible between the first and second dip but at least one hour. The second dip should be as short as possible in order to prevent dissolving of the first deposit.

The longer the first application has had time to set up, the longer it will take to dissolve, so give it more time in between (preferably the full three days).

Other Applications:

Microseal can be used for sealing porous welds, leaky joints & porous coatings or for locking screws and nuts. Application methods for these uses are the same — dipping, brushing or spraying.

Remedial Measures:

If normal application of Microseal proves unsatisfactory, the pores are probably very fine or contaminated by traces of water, grease or oxide that prevent the sealant from entering. Repeating the treatment usually gives good results.

It is also possible the pores are too large, therefore a build-up is needed. A very short soak-time (in and out) should be used in the second dip to prevent redissolving of the first dip deposit. Also, in the case of larger pores, Microseal-DS may give faster and better results.