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The Do's and Don'ts of overcoating transfers

Although we pride ourselves in supplying the thinnest and highest attainable quality Waterslide and Vinyl transfers, they are not immune to the damaging effects caused by Petrol/chemical spillages, certain degreasants and rubbing compounds and so this is why we have always highly recommended overcoating our products to protect them from such harsh products.

We understand that when it comes to overcoating our transfers, it can be a minefield, and so we have endeavoured to shed some light on the Do’s and Don’ts of overcoating our transfers.

THE DO’S

– You can use a Two-Pack Lacquer on Waterslide and Vinyl

You can use Clear Oil Based Varnish on Waterslide and Vinyl

You may be able to use some acrylic/Enamel Sprays (if you test them first and avoid cheap products)

You can overcoat the whole panel/tank or you can just overcoat to the edge of the transfer only

THE DON’TS

– You should not use Clear Cellulose and Single Pack Acrylic Sprays as this will cause the transfer to shrink

– You should not overcoat Waterslide Transfers straight away (allow at least 24 hours to dry before overcoating)

– You should try to avoid powder coating and baking the transfers as sometimes this can cause them to shrink due to the heat

– You should avoid extremes of temperature (ideally overcoat at room temperature)

We also recognise that for a long time we have been unable to recommend specific overcoating products due to manufacturers constantly changing formulas however, recently we have completed some testing on a variety of products which should point you in the right direction. Please note that you do so at your own risk.

You can read a more in depth analysis of the different overcoating products below:

CLEAR OIL BASED VARNISH

Clear Oil Based Varnish is probably one of the more traditional methods of overcoating transfers and is still widely used on much older machines to convey a more classic look. This option is mostly brushed on and so can leave brush marks if rushed or done incorrectly. Oil-based varnish, including polyurethane varnish and oil paint, can also be sprayed, of course, because any thin liquid can be sprayed. But you need to be aware of a significant difference. Varnish dries much slower than the other finishes, and unlike lacquer and water-based finish, each coat should be allowed to fully dry before the next coat is sprayed.

Most Oil Based Varnishes will take a lot longer to cure which in turn means longer times between coats. From our brief testing, the quickest drying times between coats was 6 hours or above, however, we believe you should leave it overnight for best results and apply at least 2-3 coats.

Some Oil Based Varnishes are petrol proof but from our experience it will take at least a 1-2 weeks for the varnish to fully cure and become petrol proof. If in any doubt, please test the varnish on some scrap first to see how petrol resistant it is.

Can you use Polyurethane? The short answer is yes, however it is worth pointing out this product can yellow with age on lighter surfaces and therefore it is a less favourable option. Yacht Varnishes work very well but are not necessarily petrol proof. Smaller enamel varnishes such as Revel and Humbrol which you can get from Craft shops work very well if you wish to only overcoat the transfer itself and not the whole paintwork. These seem to be petrol proof once fully cured. Always remember to clean your brush with white spirit or mineral spirits U.S.A.

Traditional Finish

Useful if you only want to overcoat the transfer and not the whole surface

Less harmful than Aerosols

✖ Longer curing times

✖ Not always petrol proof

✖ Can leave brush marks

TWO-PACK CLEAR LACQUER

Some of our customers in the specialist motorcycle painting business have perfected the art of overcoating our transfers with Two-Pack Clear lacquer. Two-pack lacquers (2K) are much more resilient but have their own application problems due to a) slower drying times and b) poisonous fumes. Even so, they are the preferred material for most motorcycle respray and repair shops and can even be bought in aersol cans. They are often based on the same resins as 2 pack paints, hence their much increased weather and chemical resistance compared to air drying lacquers.

How to apply Two-Pack: Do not add extra thinners. Generally a light mist/dust coat is applied followed by a full coat some 20-30 minutes later. Not all Two-Packs are the same quality and always refer to the manufacturers data sheets and instructions for more information.

Used by Professional Motorcycle Painting Specialists

Offers highest attainable durability of all overcoating products

Suited to heavy use areas, high temperature surfaces and other harsh environments

✖ Much more harmful. Respirator, gloves and goggles should always be worn when applying 2K

ACRYLIC/ENAMEL AEROSOLS

Acrylic/Enamel Aerosols have always been a bit of a grey area. You can purchase many of these products from shops such as Amazon and Halfords. With such a wide variety of options to chose from, it can be a bit daunting finding the perfect product. From our experience we have found it’s best skip the cheap products and buy the higher quality Aerosols only.

We have found that a lot of the products create an ‘orange peel’ effect if you do not spray a thick enough coat. This in turn creates another problem, as sometimes if you spray to heavy, the lacquer will run. The Halfords Petrol Resistant Lacquer is a good example of this. It can be hard to find the right balance.

They do have their own benefits. If you need to lacquer the surface quickly, these can be ideal due to the quick drying times between coats. A lot of them also offer a good level of UV and occasionally Petrol resistance. These products could be ideal for use on a side panel but perhaps not the best option for more complex and large surface areas.

Quick drying/curing times

Good level of UV and weather resistance

✖ Can create an ‘orange peel’ effect

✖ Can yellow lighter surfaces

✖ May not be petrol proof

✖ Inferior quality compared to 2K Products

WATER BASED VARNISH

Generally we wouldn’t recommend water-based as these are far less durable than all other options. They are usually much thinner and dry quickly. Sometimes they can leave a flatter finish than enamel. We have tried Humbrol Clear from Amazon, we brushed on 6 coats and this did provide a level of protection against petrol after two weeks however, we have not tested this outdoors for very long so we would not gurantee this.

Cures quickly/easy to apply

✖ Not very durable

✖ May leave a flat/dull finish

✖ May not be petrol proof

HINTS AND TIPS

If you have recently painted the surface, we generally suggest leaving the paint for a week to cure properly. If you apply transfers too soon, they can sometimes bubble. Many in the painting profession have mastered this and can shorten the curing times. After the paint is fully cured, apply the transfers as per our instructions. Once vinyl are applied, you can lacquer almost straight away but full adhesion will take hours. Waterslide transfers will need 24 hours to dry.

Flatting the surface before you have applied our transfers will create small channels where air can get trapped and cause the transfer to bubble. This is more apparent on waterslide transfers so apply to a smooth surface.

Remember to clean brushes used with oil based products in white spirit/mineral spirit.

Remember to wear the correct safety equipment.

CONCLUSION

We understand how daunting it is when there are so many products available and we cannot test them all, but from our research we beleive that Two-Pack Lacquer or Clear Oil based varnish will leave the best results. Most of which can offer a good resistance to Weather, UV and petrol whilst leaving a clear high quality finish. If in any doubt, use the test scrap supplied with every Vinyl Transfer order, or you can request some waterslide scrap from us.

We hope that this article has been found useful and if you have any other questions, please feel free to contact us for more information.